Lamp for mounting in an opening through a planar substrate, and an installation method

1. A lamp suitable for mounting in an opening through a planar substrate, comprising a lamp body and a mounting unit; wherein the mounting unit comprises:

a front ring for mounting against a front side of the substrate;

at least two lugs protruding backwards from the front ring, wherein each lug has an end face which functions as a pusher;

a respective slider attached to each lug which is slideable along the respective lug, wherein the slider has a slider lip at one end; and

a respective bracket pivotally connected to another end of each slider opposite to the end with the slider lip;

wherein the mounting unit is configurable between two configurations:

a first configuration in which each slider lip is spaced from the front ring, the end face of the lug is spaced from the bracket, and the bracket is free to rotate to a collapsed position in which the brackets fit through the opening; and

a second configuration in which each slider lip is against the front ring for engaging with the front side of the substrate, the end face of the lug is against the bracket and the bracket is locked in an expanded position in which the brackets do not fit through the opening and the brackets are positioned for engaging with a back side of the substrate.

2. A lamp as claimed in claim 1 , wherein one of the slider and lug comprises a slot and the other of the slider and lug comprises a pin.

3. A lamp as claimed in claim 1 , wherein each lug has a lug opening and the bracket has a hook, wherein the hook is received in the lug opening in the second configuration.

4. A lamp as claimed in claim 3 , wherein the bracket comprises a bent strip, wherein the hook comprises a projecting elbow.

5. A lamp as claimed in claim 4 , wherein the bent strip comprises a first limb having the hook, a second limb longer than the first limb, and a U-bend between the two limbs.

6. A lamp as claimed in claim 5 , wherein the first limb comprises one or more openings, slots or recesses to reduce the rigidity of the first limb compared to the second limb.

7. A lamp as claimed in claim 4 , wherein the bracket comprises a first end portion which extends from the hook, wherein the first end portion functions as a puller for pulling the hook out of the lug opening.

8. A lamp as claimed in claim 7 , wherein the bracket comprises a second end portion, wherein the second end portion is for pressing against a back side of the substrate when in the expanded position.

9. A lamp as claimed in claim 1 , comprising exactly two lugs and associated sliders and brackets.

10. A lamp as claimed in claim 1 , comprising a ceiling downlight lamp.

11. A mounted lamp assembly, comprising:

a planar substrate; and

the lamp as claimed in claim 1 mounted in an opening in the planar substrate,

wherein the mounting unit is in the second configuration, and

wherein the front ring is against a front side of the substrate, and each slider lip is pressed against the front ring by the front side of the substrate.

12. A mounted lamp assembly as claimed in claim 11 , wherein the planar substrate comprises a ceiling.

13. A method of mounting a lamp as claimed in claim 1 in an opening through a planar substrate, comprising:

setting the mounting unit in the first configuration with the brackets of the lamp collapsed;

positioning the front ring against a front side of the substrate, such that the lugs project through the opening;

advancing the mounting unit such that the slider slides until the slider lip engages with the front side of the substrate; and

further advancing the front ring of the mounting unit such that the end face of each lug performs a pushing function against a respective bracket until the front ring reaches the slider lip,

wherein when the front ring reaches the slider lip, the mounting unit is in the second configuration.

14. A method as claimed in claim 13 , comprising, during the further advancing, the end face rotates the bracket until a hook of the bracket is received in an opening in the lug.

15. A method as claimed in claim 14 , further comprising removing the lamp from the opening, by:

pulling the front ring away from the front side of the substrate until a first end portion of each bracket, which extends from the hook, contacts the back side of the substrate;

further pulling the front ring away from the front side of the substrate, causing the first end portion to pull the hook out of the lug opening and thereby release the brackets for rotation; and

further pulling the front ring away from the front side, causing the brackets to rotate to the collapsed position and allow the lamp to be removed.