Abstract:
A light fitting, particularly a built-in light fitting for ceilings and/or walls, includes an embeddable housing for receiving lighting means, a reflector, a housing frame, a functional frame, which can be detached at least partially from the housing frame and a locking device, which acts between the housing frame and functional frame. The locking device includes at least one wire spring, the wire spring being provided with a spring section extending between two locking elements formed in end areas of the wire spring. The locking elements cooperate with a respective locking receiving element in the functional frame. A wire limb is respectively formed between the spring section and locking elements. When the wire limb is pivoted and the spring section is deformed as a result, it is possible to modify the relative position of the locking elements relative to each other.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a National Stage of International Application No. PCT/EP2005/010600, filed Sep. 30, 2005, and which claims the benefit of German Patent Application No. 10 2004 048 484.8, filed Oct. 5, 2004. The disclosures of the above applications are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to a lamp, in particular a built-in lamp for ceilings and/or walls, comprising an installation housing designed for the reception of a light source, a reflector and associated mechanical and electrical and/or electronic components, a housing frame connected to the housing and a functional frame releasable from the housing frame at least regionally as well as a closing arrangement effective between the housing frame and the functional frame. 
       BACKGROUND 
       [0003]    The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
         [0004]    It is known with built-in lamps whose reflector is closed by a cover plate in the direction of illumination to fasten the cover frame holding the cover plate to the housing via a screw connection, a bayonet connection or a snap/latch connection in order to be able to carry out the changing of the light source or a cleaning procedure after releasing the corresponding connection. 
       SUMMARY 
       [0005]    It is the object of the present invention to configure the closing arrangement between the housing frame and the functional frame in a cost-effective manner in a built-in lamp of the initially named kind such that a change of light source can be carried out comfortably and without the use of tools, with it in particular being made possible also to use the closing arrangement with lamps in which the longitudinal extent of the light source coincides with the main direction of illumination. With lamps of the last-named type, it must be taken into account that, when the light source extends through and into a rear reflector opening and the reflector is coupled to the functional frame, the latter can only be pulled off in a linear fashion in the main direction of illumination and cannot, for instance, be pivoted with respect to the housing. 
         [0006]    In accordance with the invention, this object is satisfied in that the closing arrangement has at least one wire spring, in that the wire spring has a spring portion which extends between two latch elements formed in the end regions of the wire spring, in that the latch elements cooperate in each case with a latch receiver in the functional frame, in that a respective wire limb is formed between the spring portion and the latch elements so that the relative position of the latch elements with respect to one another can be changed by a pivoting of the wire limbs and a deforming of the spring portion associated therewith. 
         [0007]    The closing arrangement in accordance with the invention can thus be manufactured in an extremely cost-effective manner since it substantially only comprises one or two wire springs to be bent in the required manner in each case and latch receivers associated with them, with the latch receivers, for example, being able to be manufactured together with the functional frame by means of a single plastic injection molding procedure. If, in accordance with a preferred embodiment of the invention, the functional frame is furthermore not pivotably supported at the housing frame, but is only connected thereto via the wire springs in accordance with the invention, it is furthermore possible to pull the functional frame from the housing frame in a linear fashion in the main direction of illumination so that the use of light sources extending in the main direction of illumination is possible without problem. 
         [0008]    The housing frame is preferably received in a shape matched manner in the housing or is fixedly connected to it, in particular made in one piece with the housing, with the wire spring being arranged with its two wire limbs supporting the latch elements in two cut-outs at the outer side of the housing frame. In this manner, the closing arrangement in accordance with the invention can be integrated into the total structure of the lamp in a practically hidden manner, whereby every irritating formation of shadows is effectively avoided. If a plurality of wire springs are provided, two cut-outs of this type are provided in each case per wire spring. 
         [0009]    The wire limbs can be arranged on the outer side of the housing frame and the spring portion can be arranged on the inner side of the housing frame, with the latch elements extending inwardly through guide slots provided in the housing frame so that the wire spring is held at the housing frame in that it surrounds the housing frame along a plurality of sides and additionally extends through the guide slots into the housing frame. The provision of separate fastening means for the fixing of the wire spring at the housing frame can be saved in this manner. Since the wire spring is made as elastic, it can be clipped into the cut-outs and guide slots provided at the housing frame in a simple manner, whereupon the wire spring is connected in an unclosable manner to the housing frame and is precisely positioned in the desired manner. 
         [0010]    The wire limbs are preferably pivotable in the cut-outs provided at the housing frame in dependence on the movement of the latch elements. It is thus ensured that the wire limbs are located fully inside the cut-outs in every position they adopt on the establishing or releasing of the connection between the functional frame and the housing frame. 
         [0011]    It is particularly advantageous if the wire spring engages over the housing frame with two connection regions disposed in each case between the spring portion and the wire limbs and if the spring portion disposed at the inner side of the frame is disposed in the introductory path of the functional frame and acts on it in a resilient manner in the direction of opening. A pressure is exerted on the functional frame in its open direction by this resilient action both on the establishing and on the releasing of the connection between the functional frame and the housing frame. On the establishing of the connection, a fitter must directly overcome this pressure, whereby he is in particular also signaled by a feelable and audible latching of the latch elements that he is carrying out the assembly correctly, whereas the exertion of pressure on the releasing of the connection has the effect that the functional frame is moved away from the housing frame in the desired manner in the opening direction. 
         [0012]    In accordance with the invention, a “push-push” closing arrangement is thus in particular provided for rectangular or square downlights, wherein the specifically designed wire spring has a dual function at least in that it cooperates with the latch cut-outs for the fixing of the functional frame, on the one hand, and exerts a pre-tensioning force on the functional frame, on the other hand, which is necessary or desirable as the counter force for the operating procedure and moves the functional frame into an opening position in a compulsory manner on the opening. 
         [0013]    Alternatively to the above embodiment, wherein the wire spring has the said dual function, the resilient action on the functional frame can also be achieved by other elements than the wire spring. It is, for example, possible to arrange a respective separate spring element, in particular a respective spiral spring, in the corner regions of the housing frame and of the functional frame, said spiral spring being connected either to the housing frame or to the functional frame. These spring elements are disposed in the introductory path of the functional frame and act on it resiliently in the opening direction. The spring elements are preferably inserted in bores which are formed in the corner regions of the housing frame and are open in the direction of the functional frame. 
         [0014]    It is of advantage in this alternative embodiment that a canting of the functional frame on the fastening to the housing frame or on the release from the housing frame is particularly effectively avoided. 
         [0015]    The last named variants in accordance with the invention can be realized cost-effectively with high functional reliability, for example in that the latch elements are formed by a respective angled end region of the wire spring extending through the guide slots in the housing frame and in that the respective latch receiver belonging to a latch element has a move-in track and a move-out track as well as a latch position provided therebetween, with the latching and unlatching of the latch elements taking place by exertion of pressure onto the functional frame in its closing direction. The use of the principle in accordance with the invention is particularly sensible in lamps of the already initially named type which only permit a linear pulling off of the functional frame in the main direction of illumination since a pivoting of the functional frame is not possible as a result of the light source extending through the reflector or would only be possible if the loss of large reflector surfaces were accepted as a result of a correspondingly large rear reflector opening. In the last-named lamp types, for example, two wire springs can be provided at mutually oppositely disposed sides of the housing frame, which is in particular rectangular or square, so that ultimately a latch element is located in each corner region of the housing frame. 
         [0016]    A peripheral seal, in particular labyrinth seal, is preferably formed in the introduced and latched position of the functional frame between it and the housing frame to achieve a dust-free closing. 
         [0017]    The functional frame can be made in the already explained manner as a support of a reflector or at least of a part reflector. It can furthermore, additionally or alternatively to a light impermeable cover plate, also support a diffuser plate through which diffuse light can exit from the lamp. 
         [0018]    It is furthermore advantageous for the functional frame to be coupled to at least one flexible holding element which continues to connect the functional frame to the housing frame in its position released from the housing frame. It is thus prevented that a fitter has to handle a separate component, that is the functional frame with the elements located therein, on the changing of a light source or on the carrying out of a cleaning procedure. The functional frame can rather be let go of by the fitter after a release from the housing frame since it continues to hang at the housing frame via the flexible holding element. To end the installation process, the functional frame hanging at the housing can simply be gripped again and connected to the housing frame. 
         [0019]    Two flexible holding elements are preferably attached to a side of the functional frame so that it cannot rotate around a vertical axis with respect to the housing frame. The installation process following a change of light source, for example, is thereby facilitated since the frame already hangs in a largely correct position at the housing frame and can accordingly not be orientated incorrectly relative to the housing by the fitter on the installation. 
         [0020]    It is particularly economic if the holding elements are shaped in one piece with the functional frame, with the functional frame in particular being able to be made as a plastic injection molded part. In this case, the functional frame and the holding elements can then be manufactured in a simple manner by means of a single injection molding process. 
         [0021]    So that the holding elements are no longer visible with an installed functional frame, they can be pushable into the lamp housing or the housing frame with their region remote from the functional frame during the assembly. On the disassembly, in contrast, the holding elements are pulled out of the housing or out of the housing frame, with them, however, being fixed in their end position in the housing or in the housing frame so that they cannot be fully moved out of the housing or housing frame. 
         [0022]    Further preferred embodiments of the invention are described in the dependent claims. 
     
    
     
       DRAWINGS 
         [0023]    The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
           [0024]      FIG. 1  is a three-dimensional view of a functional frame in accordance with the invention with two wire springs; 
           [0025]      FIGS. 2   a  to  2   d  are schematic side views of a functional frame in accordance with  FIG. 1  with different positions of a wire spring on the introduction into and the moving out of latch receivers in accordance with the invention; 
           [0026]      FIG. 3   a  is a three-dimensional view of a lamp housing in accordance with the invention with a housing frame to which a functional frame in accordance with  FIG. 1  is fastened; 
           [0027]      FIG. 3   b  is a view in accordance with  FIG. 3   a  in which the lamp housing is shown as transparent; 
           [0028]      FIG. 4  is a three-dimensional view of a functional frame in accordance with  FIG. 1  with two holding elements shaped thereon; 
           [0029]      FIG. 5  illustrates a functional frame in accordance with  FIG. 4  which is coupled via the holding elements to a lamp housing or to its housing frame; 
           [0030]      FIG. 6  illustrates a functional frame in accordance with  FIG. 5  folded away from the housing frame; and 
           [0031]      FIG. 7  is a view of an alternative embodiment of the invention in accordance with  FIG. 3   b.    
       
    
    
     DETAILED DESCRIPTION 
       [0032]    The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
         [0033]      FIG. 1  shows a substantially square functional frame  10  in which a cover plate  12  as well as a reflector  14  are held in a suitable manner. The functional frame  10  has a peripheral side wall which extends perpendicular to the cover plate  12 . In two mutually oppositely disposed side walls, two respective latch receivers  16  are formed which are located in the end regions of the respective side walls so that ultimately one latch receiver  16  is present in each corner region of the functional frame  10 . In an alternative embodiment of the invention, two respective latch receivers  16  could also be formed at all four sides of the functional frame  10 . 
         [0034]    Each latch receiver  16  has a move-in track  18  as well as a move-out track  20  between which a latch position  22  is formed. The move-in track  18  has a funnel-like expanded portion  24  in its upper region via which latch elements  26  of a wire spring  28  can be inserted into the move-in track  18  in the relaxed state of the wire spring  28 , initially without deformation of the same. 
         [0035]    The embodiment of the wire spring  28  will be explained in the following with reference to the coordinate system drawn in  FIG. 1 . The axes x and y of this coordinate system span that plane in which the cover plate  12  extends. The axis z extends perpendicular to this plane. 
         [0036]    The wire spring  28  has a central spring portion  30  which extends in the direction of the axis y and is bent in the manner of a coil in order thus to amplify the spring effect. The spring portion  30  is adjoined at both sides by two wire portions  32  which extend in a straight direction obliquely upwardly within the plane spanned by the axes y and z and which are angled in their end region remote from the spring portion  30  such that they extend parallel to the axis y. 
         [0037]    Connection regions  34  respectively adjoin the ends of the wire portions  32  remote from the spring portion  30  and extend parallel to the axis x, outwardly seen from the reflector  14 . 
         [0038]    A wire limb  36  in each case in turn adjoins the connection regions  34  and extends downwardly parallel to the axis z starting from the respective connection region  34  and in each case supports a latch element  26  at its lower end. The latch element  26  extends parallel to the axis inwardly toward the reflector  14 . 
         [0039]    The total wire spring  28  with spring portion  30 , wire portions  32 , connection regions  34 , wire limbs  36  and latch elements  26  is produced from a single wire piece which is bent in each case in the desired manner and has elastic properties so that it in particular returns to its original shape again after a deformation of the spring portion  30  taking place in moderation. 
         [0040]    The cooperation between the two wire springs  28  and the four latch receivers  16  described in the following in connection with  FIGS. 2   a  to  d  makes it possible that the functional frame  10  can be released from or coupled to a lamp housing, not shown in  FIG. 1 , parallel to the direction z so that a light source extending along the direction z can be moved into and out of a rear reflector opening  38 , without the reflector  14  and the light source colliding with one another. 
         [0041]      FIGS. 2   a  to  d  illustrate that the latch receivers  16  each have an arcuate inwardly arched move-in track  18  beneath the funnel-like expanded portion  24 , said move-in track continuing obliquely upwardly outwardly in a hook form after reaching a lower end point  40  until a latch position  22  disposed approximately beneath the expanded portion  24  is reached. A first portion of a move-out track  20 , which extends up to a further lower end point  42 , then obliquely downwardly outwardly adjoins the latch position  22 . Starting from this further lower end point  42 , the move-out track  20  in turn continues obliquely upwardly outwardly so that it ends in each case outside the expanded portions  24 . In the region of the further lower end point  42 , the move-out track  20  has a step  44  which is configured such that the region of the move-out track  20  disposed after the step  44  in the direction of the arrows drawn in  FIG. 2   a  is disposed lower, i.e. closer to the reflector  14 , than the region of the move-out track  20  located in front of the step  44 . 
         [0042]    The wire spring  28  is coupled in the already explained manner to a housing frame not shown in  FIGS. 1 and 2   a - d  for reasons of clarity. On the introduction of the functional frame  10  into this housing frame, the wire spring  28  is located in its relaxed position shown in  FIG. 2   a  so that the two latch elements  26  are located directly above the expanded portions  24 . If the functional frame  10  is now moved upwardly in the direction of the housing frame or in the direction of the wire spring  28 , the latch elements  26  move into the expanded portions  24  and from there along the triangular arrows drawn in  FIG. 2   a  through the first portion of the move-in track  18 . In this way, the latch elements  26  are moved closer to one another due to the shape of the move-in track  18  so that the spring portion  30  arches upwardly in accordance with  FIG. 2b  and the two ends  46  of the spring portion  30  abut the upper edge  48  of the functional frame  10  and thus act on it with pressure. The last-named effect also exists when the latch elements  26  in accordance with  FIG. 2   b  are located at the lower end point  40  of the move-in track  18 . In this position, the two wire limbs  36  are inclined to one another and the spring portion  30  continues to arch upwardly. 
         [0043]    To move the functional frame  10  out of its position shown in  FIG. 2   a  into the position in accordance with  FIG. 2   b,  it is necessary to press it upwardly against the force of the spring portion  30  in the direction of the housing. This movement is then ultimately bounded by the cooperation of the latch elements  26  with the lower end points  40  of the move-in tracks  18 , whereupon the functional frame  10  can be let go of by the fitter. This then has the effect that, due to the pressure action induced by the spring portion  30  or its ends  46 , the functional frame  10  is moved downwardly, with the spring portion  30  simultaneously relaxing a little so that the wire limbs  36  with the latch elements  26  arranged thereon are pivoted outwardly somewhat. The latch elements  26  thus then move into the latch position  22  in accordance with  FIG. 2   c.  In this position, the downward movement of the functional frame  10  is bounded by the cooperation of the latch elements  26  and the latch positions  22 . The wire limbs  36  are only slightly mutually inclined and the spring portion  30  is only slightly upwardly arched. In this position in accordance with  FIG. 2   c,  however, the ends  46  of the spring portion  30  still also exert a specific pressure onto the upper edge  48  of the functional frame  10  such that the functional frame  10  is clamped and fixed in this position so-to-say between the latch elements  26  and the ends  46  of the spring portion  30 . 
         [0044]    If now the functional frame  10  is again pressed upwardly by the fitter to release the functional frame  10  from the housing (not shown) or from the wire springs  28 , the latch elements  26  first abut the slope  50  of the move-out track  20 , with this slop  50  then guiding the latch elements  26  to the lower end point  42  of the move-out track  20 . The latch elements  26  spring over the steps  44  directly in front of this lower end point  42  so that the latch elements  26  latch behind the steps  44 . This latching procedure is achieved in that the base of the move-out track  20  is elevated in front of the step  44  so that the latch elements  26  press onto the base of the move-out track  20  due to the elasticity of the wire springs  28  and thus spring behind the step  44  onto the base of the move-out track  20  disposed lower there. 
         [0045]    If the latch elements  26  are located at the lower end points  42  of the move-out tracks  20 , the spring portion  30  is again arched somewhat more pronouncedly than shown in  FIG. 2   c  so that the functional frame  10  is again pressed somewhat downwardly over the ends  46  of the spring portion  30  after ending of the pressure application by the fitter. The latch elements  26  move obliquely upwardly within the move-out tracks  20 . Due to the oblique configuration of the move-out tracks  20 , the functional frame  10  can, however, not fall down in an unintended manner since it continues to be held by the latch elements  26  which contact the inner sides of the move-out track  20 . Only when the functional frame is actively pulled downwardly by the fitter does a spreading open of the wire springs  28  take place in which the latch elements  26  are moved further apart. This movement can be seen from  FIG. 2   d.  If this movement is continued beyond the position shown in  FIG. 2   d,  the latch elements  26  ultimately move completely out of the move-out tracks  20  in the arrow direction so that the functional frame  10  is completely released from the wire springs  28 . 
         [0046]    After this complete release, the wire springs  28  again spring back into their position in accordance with  FIG. 2   a.    
         [0047]      FIG. 3   a  shows, in a perspective view, a lamp housing  52  having a housing base  54  disposed against the main direction of illumination. In the main direction of illumination, the lamp housing  52  has a housing frame  56  which is made in one piece with the remaining housing part. Fastening means  58  are provided at the lamp housing  52  and the lamp housing can be fixed in a suspended ceiling, for example, by means of them. 
         [0048]    Two cut-outs  60  which are substantially in the shape of a circle sector and in which the wire limbs  36  of the wire springs  28  are received are provided at two oppositely disposed sides of the housing frame  56  of which only one can be seen in  FIG. 3   a.  In the lower region of the cut-outs  60 , guide slots  62  are formed which have the shape of an arc of a circle so that the latch elements  26  connected to the wire limbs  36  can move in the guide slots  62  such as was explained in connection with  FIGS. 2   a  to  d.    
         [0049]    Since the latch elements  26  are located within the guide slots  62 , since the wire limbs  36  contact the outer side of the housing frame  56  and since the wire portions  32  connected to the wire limbs  36  via the connection regions  34  and with the spring portion  30  (not visible in  FIG. 3   a ) lie on the inner side of the housing frame  56 , it is ensured that the wire spring  28  is fixed in the desired position without additional fastening means at the housing frame  56 . The just explained position of the wire portions  32  as well as of the spring portion  30  can be seen from  FIG. 3   b  in which the lamp housing  52 , including the housing frame  56 , is shown in transparent form. It is, however, also possible to fasten the connection regions  34  of the wire spring  28  to the housing frame  56  in order thus to ensure a particularly good movability of the latch elements  26  within the guide slots  62 . Such a fastening can, for example, be achieved with a cover metal sheet  70  (see  FIGS. 3   a, b ), by means of which the connection regions  34  are clamped between the housing frame  56  and the cover metal sheet  70 . 
         [0050]    It can furthermore be seen from  FIG. 3   b  that the functional frame  10  is introduced inwardly into the housing frame  56  and the spring portions  30  act on the upper edge of the functional frame  10 . 
         [0051]      FIG. 4  shows the functional frame  10  in accordance with  FIG. 1  in a perspective view from obliquely below, with, here, however, in contrast to  FIG. 1 , two mutually spaced apart lug-like flexible holding elements  64  being provided at a side of the functional frame  10  which has no latch receivers  16 . The holding elements  64  extend perpendicular away from the said side of the functional frame  10 . At their end remote from the functional frame  10 , the holding elements  64  each have a longitudinal slot  66  as well as two outwardly facing hook-like elements  68  which serve for the anchorage of the holding elements  64  in the lamp housing  52  ( FIG. 3   b ). 
         [0052]    When the functional frame  10  is released from the housing frame  56  and pulled out of it in the already explained manner, the holding elements  64  are simultaneously also pulled so far out of the housing frame  56  in accordance with  FIG. 5  until the hook elements  68  abut the housing frame  56  in the position shown in  FIG. 5  and thus prevent a further movement of the holding elements  64 . In this position, the functional frame  10  can now be let go of by the fitter, whereupon it pivots away from the housing frame  56  due to the flexibility of the holding elements  64 , as is shown in  FIG. 6 . In the position in accordance with  FIG. 6 , the interior of the lamp housing  52  can be accessed freely and without problem, for example for the purpose of changing a light source. 
         [0053]    After such a changing of a light source, the functional frame  10  is simply gripped again by the fitter and is moved into the housing frame  56 , with simultaneously a pushing of the holding elements  64  into the cut-outs of the housing frame  56  provided for this purpose taking place in a compulsory manner. The pressing of the functional frame  10  into the housing frame  56  is continued for so long until the latch elements  26  of the wire springs  28  latch into the latch positions  22 . 
         [0054]      FIG. 7  shows an embodiment of the invention modified with respect to  FIG. 3   b.  A substantial difference consists here in the form of the wire spring  28 ′ which, unlike  FIG. 3   b,  does not have any middle spring portion  30  and also no wire portion  32  extending obliquely thereto. The spring  28 ′ is rather bent substantially in a U shape and is fastened to the housing  54 ′ by means of two respective fixing lugs  72  in its two corner regions. The wire limbs  36  are also pivotable in this embodiment such that the latch elements connected to them can move freely inside the guide slots  62 . On such a movement of the wire limbs  36 , however, the portion of the wire spring  28 ′ connecting the two wire limbs  36  to one another does not move. 
         [0055]    As a result of the described shape of the wire spring  28 ′, no pre-tension is exerted on the functional frame  10  on the introduction of the same into the housing  54 ′ as is given by the spring portion  30  in accordance with  FIG. 3   b.  To nevertheless achieve such a pre-tension, respective spiral springs  74  are attached to the four corner regions of the housing  54 ′ and these spiral springs project out of corresponding cut-outs of the housing  54 ′ in the direction of the functional frame  10 . On the introduction of the functional frame  10  into the housing  54 ′, these spiral springs  74 ′ are pressed together so that the effect of the pre-tensioning described in connection with  FIG. 3   b  is also effected here. In a corresponding manner, the spiral springs  74  also ensure that the functional frame  10  is pressed out of the housing  54 ′ on a release of the functional frame from the housing  54 ′. 
         [0056]    The description is merely exemplary in nature and, thus, variations that do not depart from the gist of the present disclosure are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the present disclosure. 
       REFERENCE NUMERAL LIST 
       [0000]    
       
           10  functional frame 
           12  cover plate 
           14  reflector 
           16  latch receiver 
           18  move-in track 
           20  move-out track 
           22  latch position 
           24  expanded portion 
           26  latch elements 
           28  wire springs 
           28 ′ wire springs 
           30  spring portions 
           32  wire portions 
           34  connection regions 
           36  wire limbs 
           38  rear reflector opening 
           40  lower end point 
           42  lower end point 
           44  step 
           46  ends of the spring portion 
           48  upper edge of the functional frame 
           50  slope 
           52  lamp housing 
           54  housing base 
           54 ′ housing 
           56  housing frame 
           58  fastening means 
           60  cut-out 
           62  guide slots 
           64  holding elements 
           66  longitudinal slot 
           68  hook elements 
           70  covering metal sheet 
           72  fixing lugs 
           74  spiral springs