GB2242475A - Latchbolt and closure assembly - Google Patents

Abstract

A latch assembly, a closure unit which comprises a latch assembly and a method of assembling the latch assembly and closure unit. The latch assembly 1 has a latch 2 received in a cavity 36 of a panel 5 (fig. 15). The latch 2 has a bolt portion 6 with a chamfered face 15 to facilitate latching engagement. A leaf spring member 3 and a finger plate 24 are secured to the latch 2 within the cavity 36 by a snap engaging stud 22 so that leaf springs 18, 19 react between the panel 5 and the latch 2 to bias the latch in a latching sense. The latch 2 has a bifurcated end 10, 11 within which is received a wall portion 37 of the panel 5. Formed in the wall portion 37 is a slot 40 offset from a centre line 12 of the latch. During fitting of the latch member to the panel 5 a web 13 in the bifurcated end 10, 11 engages with the slot 40 to determine the directional orientation with which a chamfered face 15 on a bolt portion 6 of the latch is presented for latching purposes. The web 13 may be omitted so that the latch 1 can be relatively inverted and fitted to the panel 5 with the wall portion 37 received in the bifurcated end 10, 11, the chamfered face 15 may then be presented optionally in either sense of direction during assembly of the closure unit. Preferably the latch 2, spring 3, finger plate 24 and at least part of the panel 5 forming the cavity 36 are plastics mouldings. <IMAGE>

Description

TITLE "A closure unit, a latch assembly for such a unit, and a method of assemblinq the latch assembly and closure unit" TECHNICAL FIELD & BACKGROUND ART The present invention relates to a closure unit, a latch assembly for such a unit and a method of assemblina the latch assembly and closure unit.

Latch assemblies are well known for fastenina or holdina a component to which they are fitted relative to a further component, typically for fastenina a door, Panel or wall component relative to a frame or wall on which that component may be hinqedly mounted. Usually such assemblies have a sorina loaded latch member which is to be lonaitudinally displaceable aaainst its sprina biasina to moe into enqaaement, possibly snap enaaaement, with a rebate or recess to effect fastening and it is an object of the Present invention to provide a latch assembly which is relatively simple in both structure and operation, lends itself to relatively inexpensive manufacture, Preferably by lzse of plastics mouldinas, and may easily and auickly be fitted to a component for latchina thereof.

Conventionally latch members are provided with a tonaue or bolt portion which projects from the component to which the latch assembly is fitted for latchina purposes and this tonaue or bolt portion has on one side a chamfered face to facilitate its latchina enaaaement and on the oPDosite side an abutment face to retain the latch closed.

It is important to ensure that the latch member is fitted to the component for the chamfered face to be presented correctly to facilitate latchina. Freauently an article of manufacture may include two or more similar latch assemblies which, accordinq to the desian of the article, may reouire the chamfered faces of the respective latch members to be directed in relatively opposite senses.

This can lead to confusion durina assemblv of the articles and the fittina of the latch assemblies whereby a Particular latch member may be inadvertently fitted with its chamfered face the wrong way round and it is a further object of the Present invention to Provide a closure unit having a latch assembly by which this problem may be alleviated.

STATEMENTS OF INVENTION & ADVANTAGES According to the present invention there is Provided a closure unit comprisina a latch assembly fitted to a component member; the latch assembly havina a lonaitudinally extendina latch member lonaitudinally slidable on the comPonent member, said latch member havina a tonaue or bolt Portion projectina from the component for latchina Purposes, said tongue or bolt portion havina a chamfered face to facilitate latchina enaaaement, and sprina means reactina between the latch member and the component member to bias the latch member lonaitudinally in a latchinq sense, and wherein latch orientatinq means is provided which enaaaes between the latch member and the component member and is offset from a centre line of the latch member, said means servina to determine the directional orientation of the chamfered face relative to the component member durinq fittina of the latch member to the component member.

Further accordina to the present invention there is provided a method of assemblina a closure unit as specified in the immediately erecedina paraqraph which comPrises providina a cavity in the component member, said cavity formina a wall part havina an aperture therein throuah which the latch member is to project from the component member for latchina Purposes, insertina the latch member throuah said aperture for the latch orientatina means to ensure between the latch member and the component member and provide a Predetermined directional orientation for the chamfered face relative to the component member, and securina said sprina means to the latch member to react in the cavity between the latch member and the component member.

The component member will usually be in the form of a wall or lid, typically of a plastics container in which the latch member is intended to latch encase and retain closed a further component which will usually be hinoedly mounted with respect to the first mentioned component.In such an arranaement the latch member will reauire its chamfered face to be directed in a Predetermined sense with respect to the component member on which it is carried so that durinq closure the chamfered face abuts the closing member to displace the latch member lonaitudinally aqainst its sorina biasina and effect snao enaaaement latchins. By the present invention the latch orientatino means which enaaaes between the latch member and the component member and is offset from the lonqitudinally extendina centre line of the latch member ensures that during assembly of the latch member with the component member the chamfered face of the tonaue or bolt Portion will be correctly presented as aforementioned to Facilitate the latch enaaoement. The offsettina of the latch orientatina means should ensure that for the particular structure of closure unit under consideration, the latch member cannot inadvertently be fitted to the comnonent member with the chamfered face the wrong way round. This is most advantaqeous for larae volume production of Plastics articles, such as containers, havina closure units where it may be ensured that the latch assemblies can only be fitted to the component members with the chamfered faces of the tongue or bolt portions correctlv orientated with respect to the comoonent member on which they are carried.Desirably the component member (or at least that part to which the latch assembly is fitted) is formed as a plastics mouldina and also the latch member is formed as a plastics mouldina to incorporate the latch orientatina means which enaaaes between the latch member and the component member.

The latch orientatina means may comprise a lonaitudinallv extending track on one of the latch member and component member and a track follower on the other of those members so that the track follower enaaaes with the track during fitting of the latch member to the component and is slidably displaceable alona the track durina lonaitudinal displacement between the latch and component members as the latch is enaaaed and disenaaaed. The track may be in the form of a lonaitudinally extendina slot or recess in the latch member or the component member and the track follower may be in the form of a projection on the component or latch member as the case mav be which enaaaes in the slot or recess.In a preferred arranaement the lonaitudinal end Part lenath of the latch member remote from its tonaue or bolt portion is bifurcated to comprise opposed wall parts between which a wall section of the component member is received to Partly retain the latch member in the component member. The latch orientatina means conveniently enaaqes between the bifurcated end of the latch member and the wall section which is received within that end. The oDosed wall parts of the bifurcated end of the latch member may be interconnected by a web offset from the centre line of that member and the wall section of the component member received between the oPPosed wall Parts may have a lonaitudinally extendina slot within which the web is slidably received to determine the directional orientation of the chamfered face on the latch member relative to the component member.

Still further accordina to the Present invention there is Provided a latch assembly for fittina to a component to provide a closure unit which comprises a lonaitudinally extendina latch member which is to be lonaitudinally slidable in the component and has a tonaue or bolt Portion which is intended to Project from the component for latchinq purposes, a sprina member which is to be retained in said component for biasina the latch member lonaitudinally in a latchina sense and which has a head part and a sprina Part, and snao enaaaina stud means extendina laterally between the head part and the latch member and by which the head part of the sprina member is secured to the latch member for unified lonaitudinal displacement therewith.

The invention also provides for a method of assemblina the latch assembly as specified in the immediately Precedinq Paragraph to a component to provide a closure unit which comprises providing the component with a cavitv havina a wall part with an aperture therein throuah which the latch member is to Project from the component for latchina purposes, insertina the latch member throuah said aperture and snaD enaaainq the stud means to secure the sprinq member to the latch member for the scrinq Dart to react in the cavity between the latch member and the component member.

Preferably at least one of the latch and sprina members is formed as a plastics mouldina and has a laterally extendina stud intearally formed therewith for snaD enaaqement with the other member. The latch assembly may comprise a handle carried for unified displacement with the latch member to facilitate manual disDlacement of the latch member lonaitudinally aaainst its biasina. The handle is preferablv carried by a handle member secured as part of the assembly by laterally extendina snan enaaqina stud means. The handle member may be a plastics mouldina with an integrally formed stud which Drovides said snap enaaaement.For convenience of assemblina the latch assemblv, the sprina member, latch member and the handle member are secured together by a common stud which may be intearal ly formed with one of those members. In a preferred arranqement the latch member is disposed between the scrinq member and the handle member. With this latter arrandement a laterally extendina retaininq stud may be inteqrally formed or carried by one of the sprina member or handle member and extend through an aperture in the latch member to snan engage with the other of the sprina member or handle member as the case may be.In accordance with the concept of the invention where the retaining stud Provides snap enaaaement, such snap enaaqement to secure the latch and sprina members (and also the handle member when provided) toqether provides a most convenient structure for fast assembly.

The sprina part of the sprina member is conveniently formed as one or more leaf sprinas which extend from the head Part to react lonaitudinally between that part and a wall or face of the component within which the sprina member is to be fitted. Such a leaf sprina is convenient for plastics mouldina and will usually be of J or U shape.

It will be apPreciated that the sprina part can take many shapes and forms provided that this Dart serves to bias the head part and latch member for unified disPlacement lonaitudinally in a direction for the latch member to Project from the component to effect latchina.

The cavity within which the latch assembly is fitted in the component can take many forms such as a recess or aPerture in that component and within which the latch member is predominantly housed. The cavity may indeed merely comprise a frame formed by upstandina flanaes on a side face of the comPonent and which is approPriately shaped to accommodate the latch assembly.The latch assembly is conveniently retained in the cavity of the component partly by location of the tonque or bolt portion of the latch member within the aperture in the side wall of the cavity and partly be the end of the latch member remote from the tonaue or bolt portion slidably enqaaina with a further wall part of the cavity, for example by cooperation of a bifurcated end of the latch member closely and slidably receivina a wall section of the component as previously mentioned.

Preferably the cavity of the component which receives the sprina member is formed by a plastics mouldina: such a plastics mouldinq may be secured to the component or be intearal therewith, for example where the component is itself a plastics moulded wall, panel, door or frame.

The cavity does not necessarilv have to fully enclose the latch assembly and may, for example, in substance comPrise lonqitudinally opPosed flanges throuah one of which the tonaue or bolt portion projects and aaainst the other of which the sprina means can react.

DRAWINGS One embodiment of a latch assembly, such an assembly fitted to a component and a method of assemblina the latch assembly and component, all in accordance with the present invention will now be described, by way of examPle only, with reference to the accomPanyins illustrative drawings in which: Fiaures 1, 2, 3 and 4 are respectively an underside Plan view, a section on the line II-II of Fiqure 1, a top slan view and an end view of the latch assembly; Fiaures 5, 6, 7 and 8 are respectively an underside plan view, a section on the line VI-VI of Fiaure 5, a top slan view and an end view of a latch member incorporated in the latch assembly of Fiqure 1:: Fiaures 9, 10 and 11 are respectively a top plan view, a section taken on the line X-X of Figure 9, and an underside plan view of a sprina member incorporated in the latch assembly of Fiqure 1: Fiaures 12, 13 and 14 are respectively an underside plan view, a section taken on the line XIII-XIII of Fiaure 12, and a toP slan view of a handle member incorporated in the latch assembly of Figure 1: Fiqure 15 is a perspective view of part of a component to which the latch assembly of Fiqure 1 is to be fitted; Fiaure 16 is a olan view of a closure unit comprising the latch assembly of Fiqure 1 fitted to the component of Fiqure 15, and Figure 17 is a section of the closure unit taken on the line XVII-XVII of Fiaure 16.

DETAILED DESCRIPTION OF DRAWINGS The latch assemblv 1 shown in Fiaures 1 to 4 has a three Part structure, each of which parts is formed as a plastics mouldina and consists of a latch member 2, a sDrina member 3 and a handle member 4. Althouah in Fiaures 1 to 4 the latch assembly is shown assembled, the assembled structure will not normally be provided until the latch assembly is fitted to a component 5 (see Fiaures 15 to 17) which, typically, comprises a plastics moulded Panel formina a hinqed wall or door of a Plastics container that is to be releasably fastened bv the latch assemblv to a frame or further wall of the container.

The latch member 2 (Fiaures 5 to 8) has a aenerally rectanaularly sectioned, hollow, bolt portion 6 extendina lonqitudinally from which is a rectanqularly sectioned shank Portion 7. The shank Portion 7 is recessed or waisted adjacent to the bolt portion 6 to provide rectanaular seats 8 and 9 in opposed side faces of the latch member. The end of the shank portion 7 remote from the bolt portion 6 is bifurcated to provide opposed wall Parts 10 and 11 which extend lonaitudinally of latch member.The wall Parts 10 and 11 are substantially Parallel with the aeneral plane of the bolt Portion 6 and, overall, the latch member has a lonqitudinally extendina centre line 12 on each side of which (in the plan view) its shape is substantially symmetrical other than for a lonaitudinallv extendina web 13 which is located between and interconnects the opposed wall parts 10 and 11. The web 13 is offset (in plain) from the centre line 12 and extends Parallel thereto as will be seen from Fiaures 5 and 7. Located in the seatinas 8 and 9 and extendina laterally throuah the shank portion of the latch member is an aperture 14. The bolt portion 6 has at its end remote from the shank portion a chamfered face 15 which subtends an acute angle with a substantiallv flat lonaitudinally extendina abutment face 16 of the bolt Portion.

The sprint member 3 (Fiqures 9 to 11) has a head Dart 17 in the form of a substantially flat rectanaular mountina Plate extendina from which is a sprint part formed by two cantilevered leaf sprints 18 and 19 of substantially J shape. Located centrally in the head Part 17 is an aperture 20.

The handle member 4 (see Fiqures 12 to 14) has a substantially flat rectanaular mountina Plate 21 located centrally within which is an intearal stud 22. The stud 22 projects perpendicularly from the plane of the plate 21 and at its free end hns a barbed flanae 23. Located alona a side edce of the mountina slate 21 is an intearal finder plate 24 which projects from the mountina Plate in the opposite sense of direction to that of the stud 22.

The three members 2, 3 and 4 which constitute the latch assembly are intended to be assembled as shown in Fiaures 1 to 4. In this assembly the head plate part 17 of the sprina member 3 is located as a close complementary fit within the seatinq 8 of the latch member so that the aperture 20 co-incides with the aPerture 7 and the leaf sprina parts 18 and 19 are directed lonqitudinally towards the bifurcated end of the latch member. The handle member 4 is now fitted to the latch member on the side thereof opposite to the sprina member by locatina the stud 22 to co-incide with the aperture 7 and then pressing the handle member so that the stud passes laterally and successively throuqh the apertures 7 and 20 for the barbed flange 23 to snap encase over the head Plate 17 of the sprina member.

In this latter condition the mountina plate 21 is received as a close complementary fit within the seatina 9 with the finaer Plate 24 projecting outwardly of the latch member.

The snap enqaaement of the barbed flanqe 23 over the sDrinq member and the co-operation of the sprinq member and handle member in their respective seatinas in the latch member will usually provide a riaid structure for the latch assembly. It will be seen from Fiaures 1 and 3 that the latch assembly has an overall confiquration which, in plan, is symmetrical on each side of the centre line 12 other than for the provision of the web 13 in the bifurcated end of the latch member.

The panel component 5 (see Figure 15) to which the latch assembly 1 is to be fitted is provided with a cavity 30 (which is conveniently moulded therein) adjacent to an edae 31 of the panel forming a wall 33 between the edae 31 and the cavity 30. Extendina lonaitudinally throuah the wall 33 between the cavity and the edae 31 is a rectanaular aperture 34 which is substantially complementary in lateral section to that of the bolt Portion 6. For convenience of description the panel component 5 may be rewarded as a lid or wall member which is hinqedly mounted as indicated at 35 for Pivotal movement about an edae parallel to the edae 31 so that the edqe 31 may, typically, move into latchina enaaaement with a frame (not shown) for, or a further panel (not shown) adjacent to the panel 5.The latch assembly 1 is, Predominantly, to be housed within the cavity 30 which comPrises an aperture 36 in the panel and a thin walled section 37 of the panel. The wall section 37 is substantially coplanar with the aperture 34 and extends lonqitudinally in alignment with that aperture. It will be seen from Fiaure 15 that the wall section 37 is formed by lonqitudinally extendinq rectanaular recesses 38 and 39 which are moulded in ooposed faces of the Panel and open into the cavity aperture 36. The aperture 34 for the bolt portion, the cavity aperture 36 and the recesses 38 and 39 are substantially symmetrical in the Plane of the panel on each side of a lonqitudinally extendinq centre line 12'.

Formed in the wall section 37 is a slot 40 which is offset to one side of the centre line 12' and extends parallel therewith to ocen at 41 into the cavity aperture 36.

To Provide the closure unit shown in Fiaures 16 and 17 where the latch assembly is fitted to the panel component 5, the latch member 2 with its bifurcated end leadina is inserted throuqh the aperture 34 in the wall 33 so that the bifurcated end moves lonaitudinally into the cavity aperture 36 with the opposed wall parts 10 and 11 of the bifurcated end in planes which are substantially Parallel to and on opposite sides of the plane of the panel wall section 37. Continued insertion of the latch member into the Panel 5 causes the wall section 37 to be received between the opposed walls 10 and 11 at the bifurcated end of the latch member and also the web 13 in the latch member to be slidably received within the elongated slot 40. The bifurcated end part lenath of the latch member is received as a substantially complementary slidina fit within the recesses 38 and 39 of the panel component with the centre lines 12 and 12' substantially coincidina as shown in Figure 16 (in this Figure part of the wall part 11 on the shank portion 7 is shown cut-away to illustrate the enaaaement of the web 13 in the slot 40). The sprina member 3 and handle member 4 are now located in the cavity aperture 36 on opposed sides of the latch member 2 and are firmly attached thereto by the laterally ntendina stud 22 to be located in the seatinas 8 and 9 and form the unified latch assembly 1 as previously described (and which assembly will be apparent by comparison of Fiaures 2 and 17).With the latch assembly thus fitted, the free ends of the leaf sprinqs 18 and 19 react aaainst abutment faces 50 of the Panel component within the cavity aperture 36 to bias the latch member 2 lonaitudinally (and leftwardly in Fiqures 16 and 17) with respect to the panel 5 for conventional latchina enaaqement of the bolt portion 6.

As the bolt portion 6 moves into latchinq enaaaement in conventional manner the latch member will be displaced riqhtwardly with respect to the panel 5 and into that panel (aaainst the biasinq of the leaf sprinqs 18 and 19) while the bifurcated end wall Parts 10 and 11 slide over the panel wall section 37 and the web 13 slides alona the slot 40. The finqer plate 24 of the handle member projects laterally from the panel component 5 as shown in Fiaure 17 to facilitate manual ensaqement of the latch assembly for withdrawinq the bolt portion 6 aqainst the sprint biasinq to release the latch.

Once the latch assembly 1 has been assembled in the panel 5, inadvertent removal of the latch member 2 is prevented by the bolt portion 6 beina captured within the aperture 34, the enaaaement of the bifurcated end part lenqth of the latch shank with the panel wall section 37 and the abutment of either or both of the panel parts 17 and 21 of the sprina and handle members aaainst the face of the wall 33 in the cavity aperture 36 under the biasinq of the leaf sprinqs.

From Fiaure 17 it will be appreciated that the relative positions of the sprina member 3 and handle member 4 can be reversed on the latch member 2 so that the finder plate 24 may project downwardly in that Fiaure if such Dositioninq is more convenient for releasina the latch.

In accordance with conventional practice the chamfered face 15 on the latch member will be directed towards the closure (frame) with which the bolt portion is intended to latch so that as the latch is enaaaed, abutment of the chamfered face 15 with the closure facilitates in lonqitudinal displacement of the latch member aaainst its sprinq biasinq until the bolt Portion snap enqaaes within a rebate or recess of the closure and the bolt portion is urqed by its sprina loadina for its flat face 16 to enqaqe with the closure and secure the latch.In the embodiment as above described, the latch assembly 1 can only be fitted to the panel component 5 with the chamfered face 15 directionally orientated as shown in Fiaures 16 and 17 as this directional orientation is predetermined by the necessity for the offset web 13 to ensure within the offset slot 40. The offset web and slot provide a convenient form of track and track follower which have to be enaaaed to Permit the reauired insertion of the latch member into the panel component. Conseouently, if the latch member is inadvertently inserted into the panel back to front (that is with the chamfered face 15 relatively inverted from that shown in Fiqures 16 and 17), the web and slot cannot encase and an incorrect stave of assembly will immediately be apparent.This is particularly advantaqeous in the volume production of similar articles each of which may have two or more identical latch assemblies where the respective chamfered faces 15 are intended to be directionally orientated in relatively oPoosite directions and the slots 40 in the respective cavities may be moulded-in (effectively above or below the centre line 12' in Fiaure 15) so that the respective latch members can onlv be fitted to the panel comPonent of a particular article with their respective chamfered faces 15 Presented correctly for their intended latch enqaqement.

From the aforeqoina descriPtion of the preferred embodiment it will be recoanised that the three part snan enaaaina stricture of the latch assembly 1 permits that assembly to be constructed very simply and auickly durina its fittina to the panel component and furthermore the sprinq biased latch member is firmly retained in the closure unit. These particular advantaqes Provide an improved concept which may be used with advantaae in the absence of the latch orientatina means. Accordinaly in a further inventive structure the web 13 can be omitted from the moulded latch member so that the end part lenath of the latch member shank is wholly bifurcated to receive the panel wall section 37 (in this further structure the slot 40 may be omitted).Consequently such a latch member 2 can be received within the Panel 5 in a similar position to that shown in Fiqure 17 or relatively inverted (so that the wall part 11 underlies the wall Part 10 and the chamfered face 15 is directionally orientated downwardly in Fiaure 17). In the absence of the web 13 it will be realised that the appropriate directional orientation for the chamfered face 15 will have to be determined by the operative assemblina the closure unit.

Although the plastics mouldinq 4 has been referred to as a "handle members and a handle or finger Plate part on this member is preferred, it is to be realised that the handle or finqer plate is not necessarily located on this member 4 and can be moulded on one of the other components of the latch assembly. For examPle a finder plate can be moulded on to the latch member 2 or on to the sprint member 3 in the same aeneral location as that shown in Fiaure 17.

Indeed the latch assembly 1 may be modified to have a two member structure consistina of the sprinq member 3 and the latch member 1 where the snap enaaqina laterally extendina stud and finger plate are integrally moulded with the sprinq member 3 so that the stud snap enqaaes between the sprina member and the latch member to firmly retain the sprina member in a seating on the latch member. It is also Possible for the latch assembly which consists of the three member structure or which consists of the two member structure to have one or more snap enqaqinq studs intearally moulded with the latch member for snas enaaqement with apertures in the sprinq and handle members as the case may be (provided that there is adeauate clearance to locate the latch member with its integral stud or studs throuqh the aperture 34).

Claims (38)

1. A closure unit comprisinq a latch assembly fitted to a component member; the latch assembly havina a lonaitudinally extendina latch member lonaitudinally slidable on the component member, said latch member havina a tongue or bolt portion projectina from the component for latchina purposes, said tongue or bolt portion havina a chamfered face to facilitate latchinq engaaement, and spring means reactina between the latch member and the component member to bias the latch member lonaitudinally in a latchina sense, and wherein latch orientating means is provided which engages between the latch member and the component member and is offset from a centre line of the latch member, said means serving to determine the directional orientation of the chamfered face relative to the comPonent member durinq fittina of the latch member to the component member.

2. A unit as claimed in claim 1 in which the latch orientatinq means comPrises a lonaitudinally extendina track on one of the latch and component members and a track follower on the other of said members, the track follower beings enqaaed with the track durina fittinq of the latch member to the component member and beina slidably displaceable alone the track durina lonaitudinal displacement between the latch member and the component member.

3. A unit as claimed in claim 2 in which the track comprises a longitudinally extending slot or recess and the track follower comprises a projection enaaaina with said slot or recess.

4. A unit as claimed in either claim 2 or claim 3 in which the track comprises a lonaitudinally extendina slot in a wall of the component member within which a projection of the latch member is received.

5. A unit as claimed in any one of the precedinq claims in which the longitudinal end Part length of the latch member remote from the tonaue or bolt portion is bifurcated to comprise opPosed wall parts between which a wall section of the component' member is received to partly retain the latch member on the component.

6. A unit as claimed in claim 5 in which the latch orientating means engages between said wall section of the component member and said bifurcated end Part lenqth of the latch member.

7. A unit as claimed in claim 6 in which the latch orientating means comprises a longitudinally extendina slot in the wall section of the component member and a web formed between the opposed wall parts in the bifurcated end part lenath of the latch member and which web lonaitudinally slidably enqaaes with said slot.

8. A unit as claimed in any one of the precedinq claims in which the latch member is a plastics moulding.

9. A unit as claimed in any one of the Precedina claims in which the spring means comprises a spring member having a head Part secured for lonaitudinal displacement with the latch member and a spring Part which reacts between the head part and the component member to provide said biasing.

10. A unit as claimed in claim 9 in which the spring part comprises at least one leaf sprina carried by the head part.

11. A unit as claimed in either claim 9 or claim 10 in which the spring member comprises a Plastics moulding.

12. A unit as claimed in any one of claims 9 to 11 in which the spring member is secured to the latch member by laterally extendinq snap engaqing stud means.

13. A unit as claimed in claim 12 in which at least one of the latch member and spring member is a plastics mouldina and a stud is intearally formed therewith for snap engagement with the other member.

14. A unit as claimed in any one of the preceding claims in which the latch assembly comprises a handle secured as Part thereof for unified longitudinal displacement with the latch member, said handle projecting from the component member to facilitate manual displacement of the latch member against its biasing.

15. A unit as claimed in claim 14 and comprising a handle member secured to the latch member by snap engaging stud means.

16. A unit as claimed in claim 15 in which the handle member comprises a plastics moulding.

17. A unit as claimed in claim 16 in which the stud means comprises a stud integrally formed with the handle member.

18. A unit as claimed in any one of claims 15 to 17 when appendant to claim 9 in which the handle member and spring member are retained in engagement with the latch member by snac engagement of a common stud.

19. A unit as claimed in claim 18 in which the common stud is integrally formed with one of said members.

20. A unit as claimed in either claim 18 or claim 19 in which the latch member is disposed between the spring member and the handle member and the stud is carried by one of the spring member and handle member to extend through the latch member and snap enaaqe with the other of the spring member and handle member.

21. A unit as claimed in any one of the preceding claims in which the latch assembly is housed within a cavity of the component member with the tonaue or bolt portion Projecting longitudinally through an aperture in a side wall of the cavity for latching purposes.

22. A unit as claimed in claim 21 in which at least part of the component member formina said cavity and with which the latch member engages is a plastics moulding.

23. A closure unit substantially as herein described with reference to Fiaures 16 and 17 of the accompanying illustrative drawinas.

24. An article incorporating a closure unit as claimed in any one of the preceding claims.

25. A latch assembly for fitting to a component to provide a closure unit and which comprises a lonaitudinally extending latch member which is to be longitudinally slidable in the component and has a tongue or bolt portion which is intended to project from the component for latching purposes: a spring member which is to be retained in said component for biasing the latch member longitudinally in a latching sense and which has a head part and a spring part, and snap engaging stud means extending laterally between the head Part and the latch member and by which the head part of the spring member is secured to the latch member for unified lonaitudinal displacement therewith.

26. An assembly as claimed in claim 25 in which at least one of the latch and spring members comprises a plastics moulding and has a laterally extendinq stud integrally formed therewith for snap enqaament with the other member.

27. An assembly as claimed in either claim 25 or claim 26 and comprisina a handle carried for unified displacement with the latch member to facilitate manual disPlacement of the latch member longitudinally aqainst its biasing.

28. An assembly as claimed in claim 27 in which the handle is carried by a handle member secured as Part of the assembly by laterally extendina snap engaging stud means.

29. An assembly as claimed in claim 28 in which the handle member comprises a plastics m oul ding havinq a stud integrally formed therewith for snap engagement to secure the handle member as part of the assembly.

30. An assembly as claimed in either claim 28 or claim 29 in which the latch member, spring member and handle member are secured together by a common snap engaging stud.

31. An assembly as claimed in any one of claims 28 to 30 in which the latch member is disposed between the spring member and the handle member.

32. An assembly as claimed in claim 31 when appendant to claim 30 in which at least one of the spring member and handle membercomprises a plastics moulding having a stud integrally formed therewith and which stud extends through the latch memb-er to snap engage with the other of said spring member and handle member.

33. A latch assembly as claimed in any one of claims 25 to 32 in which the latch member has its end Part length remote from the tonaue or bolt Portion bifurcated to provide opposed wall parts for receiving therebetween a wall portion of the component during fittina of the latch assembly to the component.

34. A latch assembly substantially as herein described with reference to Figures 1 to 14 of the accompanying illustrative drawings.

35. A closure unit or article incorporating such unit which comprises a component havina fitted thereto a latch assembly as claimed in any one of claims 25 to 34.

36. A method of assemblinq a closure unit as claimed in any one of claims 1 to 23 which comprises providing a cavity in the component member, said cavity forming a wall Part havina an aperture therein throuah which the latch member is to Project from the component member for latching purposes, inserting the latch member through said aperture for the latch orientating means to engage between the latch member and the component member and provide a predetermined directional orientation for the chamfered face relative to the component member, and securing said sprina means to the latch member to react in the cavity between the latch member and the component member.

37. A method of assembling a latch assembly as claimed in any one of claims 25 to 34 to a component to provide a closure unit which comprises providing the component with a cavity having a wall part with an aperture therein through which the latch member is to project from the component for latching purposes, insertinq the latch member throuah said aperture and snap engaging the stud means to secure the spring member to the latch member for the spring part to react in the cavity between the latch member and the component member.

38. A method of assembly as claimed in either claim 36 or claim 37 and substantially as herein described.