LAMP ASSEMBLY The present invention relates to a lamp assembly.
2335027 Lamps for photography and filming work often have to satisfy particular requirements of the user, such as having a specific, often relatively high, luminescence. It is often also necessary for one filming session to have lamps of difference luminescence to cater for different lighting conditions.
Problems 7rise with prior art lamp assemblies as a result of having to have several lamps to provide different levels of lighting and back-up lamps should a bulb of one lamp fail. If no bacil-'.'.r - -amp is provided, it is often necessary to wait for the bulb -c, cool before removing it from the lamp assembly or otherw--'se to handle the hot bulb.
Anothe,-- p:7oblem encountered by known lamp assemblies relates to the generated by the lamps. Cooling may be provided by a f,-.,n r cool air passages within the assembly but this generally lleads to stray light from the sides of the assembly and hot spots on the assembly body.
The presz-.:-t invention seeks to provide an improved light assernt -V.
Accordi -9 to an aspect of the present invention, there is provid6-_J a light assembly including a lamp housing in which a light bul'-- is locatable and a bulb holder for holding a bulb, the bu-'17 '-,-1-Ier being engageable with the housing and 2 removable from the housing with a bulb in place in the bulb holder.
Preferably, the bulb holder is designed such that it is not necessary to touch the bulb on engaging or removing the bulb holder, and thus the bulb itself, into or from the housing.
There may be provided a plurality of bulb holders, each engageable with the housing. The bulb holders may be provided with replacement bulbs or bulbs of different luminescence or of different types such as arc lamps are halogen bulbs, thereby avoiding the need to have many different lamps.
According to another aspect of the present invention, there is provided a light assembly including a housing, a light bulb operable to generate light in one or more selected propagation directions and cooling means, the cooling means being operative to direct heat energy emitted from the bulb to a location removed from the or each light propagation direction.
The cooling means preferably includes a heat projector located at least in part substantially behind heat generating regions of the bulb. The preferred embodiment includes a light reflector which includes a light absorbing surface. The light absorbing surface preferably faces the heat projector, thereby to create a flow of heat from the light bulb.
The heat absorbing surface may be located on an exterior surface of the light reflector.
3 Pref erab'-,.7., light bu--'-, the assembly includes a bulb holder for holding a the cooling means advantageously being operable to direct he,-from the bulb in a direction away from the bulb holder. he bulb holder is, in the preferred embodiment, removable from the assembly with the bulb in the bulb holder, in which case it is advantageous to keep it cool.
An embod-J-z,,ent of the present invention is described below, with reference to the accompanying drawing, in which the sole Figure is a side elevational view, in partial cross-section, of a prefer- red embodiment of lamp assembly.
Referring --o the Figure, the lamp assembly shown includes a housing 10 with a light emitting face 12 and, in conventional fashion, a rotatable accessory ring 14 having two barndoors 16, a d'-cl,roic filter 18 and diffuser 20, which are all selectively movable over and away from the light emitting face 12.
At the other end of the housing 10 there is provided a plug in bulb ho"-'--er 22 which plugs into a bore 24 of the housing 10.
The bu--'..) 'rider 22 includes suitable electrical and mechanical fittings:not shown) for a bulb 26, which may typically comprise sprung electrical terminals for receiving terminal pins (not shown) of bulb 26. The bulb holder 22 is also provided with electrical connections to the power supply couplings (not shown) of the assembly, in this example includinc. an on/off switch 28 and plug option fitted on stud or shoe fixing 30. These electrical couplings will be 310 readily a-pparent to the skilled reader.
4 The bulb holder 22 is secured to the housing 10 by any suitabl, e; means, f or example by a friction f it, latch mechan.,,;?,.,., bayonet or screw mechanism. Suitable mechanisms will be readily apparent to the skilled person.
The bult 22 is also provided with a heat sink 32 in the form of,:recLsion die-cast fins extending in a direction transverse to the axis of the bulb holder and bulb and thus in a direction substantially perpendicular to the direction of heat t,-:, i-.-er from the bulb 26. The heat sink 32 ensures that handle of bulb holder 22 remains cool to the touch to enable replacement of a bulb 26 even after use when the bulb 26 1-iot.
Within housing 10 there is provided a heat propagation area 40 (.esigned to remove heat generated by the bulb 26 during The heat propagation area 40 includes a heat dissipa-:--)n chamber 42 of frusto-conical form with a narrow end a transverse flange 44 abutting a bulb holder base 4 f!:he bulb holder 22. The internal concave surface of the dissipation chamber 42 is highly reflective, while its ou±---_,_: convex surface is heat absorbing, being for example matt The ass=.-.---)ly 10 is also provided with a parabolic light reflect,-r 50 located in conventional manner to project light emitted the bulb 26 towards the light emitting face 12 of the light ---,nir- 10. The parabolic light reflector 50 includes an interial concave surface which is highly heat reflective, in con-.,z-,,,-.icl-ial manner and an outer convex surface which is heat ab,--or7"--iiig, being for example matt black.
The housing 10 of the light unit is provided with a series of transve--se ',ieat dissipation apertures 60 through which air can pass. In ---.'le example shown, the apertures are in two sets, a first se: being located around the light reflector 50 and a second set being located around the heat dissipation chamber 42.
When th- larrp is in use, the bulb 26 generates heat in conven----cnal manner. The heat dissipation chamber is designed to project the generated heat forwardly towards the outside convex of the light reflector 50 and thus away from the bac'- -,,L' the bulb 26 towards the bulb holder 22. This project-'!-,-.-. of heat in a controlled manner facilitates the design,f --he heat dissipatilon mechanism, in this example the apertur:s 53.
The arrnws 60 in r-'..-e 62,64 show the passage of air through the apertures..'1),.-ising 10, cold air passing from below and hot air passing of the housing --A from the upper apertures 62. A front-m".st ai3er-Lure 66 dissipates heat at the light emitting surface 12 c..E the unit.
Behind ".he bulb 26, any heat passing in a direction towards the handle 4 is dissipated both by the fins 32 and through absorpt'.,)r "- ,V the heat absorbing surface of the chamber 42.
It is e7-.-j4-saged in the preferred embodiment that a plurality of bulb 22 will be provided such that replacement of a bulb is by replacement of the bulb holder also. In this ma...,.r, it is not necessary to touch a bulb at any time 6 during.ice of the l--"ght unit 10. Moreover, not only can rep-1--,-:ewen-L bulbs 26 be provided with their own bulb holder 22 but it is also possible to provide bulbs of differe:- v--)es with their individual bulb holders 34 such that r-h.'a--ac-r-eristics of light unit, such as luminescence, can be;5--'-.ered simply by replacement of a bulb 26 and bulb holder 22. For he latter case, it is envisaged that the handle 3f the bulb unit 22 can be provided with a label or the lig'ri iving details, such as wattage or type, of the bulb in ques--:(-n.
It will apparent from the above that the bulb 26 is removed from the,ack of the unit 10 rather than from the front of the unit 10 -,.--ich is normally hot. This feature in conjunction with thz --eat dissipation measures described above provides an advantacz!us assembly.
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