GB2398600A - Latch having mouth part shaped to prevent deformation or accidental release - Google Patents

Abstract

A latch 28 includes a retention plate 46 having a mouth 52 to receive a striker 44 and a latch bolt 44 mounted on the retention plate to releasably secure the striker in the latch. The mouth 52 is shaped so that when latched any forces applied substantially perpendicular to the direction of latching L and in the plane of the retention plate urge the striker bar 44 against either of the angled side mouth walls 58, 60 which guide the striker towards the end surface 62 of the mouth, retaining the striker in the latched position.

Description

A Latch lain' prcse!t invcation relates to a latch. in particular to a

door latch for use on vehicles Act as autoT1lohiles car commercial vehicles.

l<ow, cl>i-,r larches include a latch bolt mounted on a latch Itousing. 'I'ypically the latch l.si leas a retention plate and the larch bolt is rotatably mounted on a pin provided on IIIC rctction plate. 'l'he latch can be mounted on a door, with a corresponding striker being unwed on part ol' a vehicle t'ramc, such that when the door is closed by moving in a liitcling, direction, it is releasably retained in the closed position by engagemcul of the striker With the latch bolt. Operation ol'a release handle releases the striker and allows the door lo he opened.

11 is inyortaTll that in the event of an accident, the door remains closed so as to prevent v<- Icicle >cculats or vehicle loads from leaving the vehicle. i'urthermorc, the door c<ihrles tats the integrity of' the vehicle, i.e. it forms part of the load path in the event of : c c idcut. (:'onscquently latches must meet certain strength requirements, in particular he chic t<, witl:.stand loads in the longitudinal, transverse, and vertical directions relative to the clicle vvitlout "'ailing, i.e. without the latch releasing the striker. 'I'lhe longitudinal directions iu1 the trasversc direction are defined by the conventional direction of travel of the velicic.

I hi l'lrct types of' vehicle have doors at dit't'erent locations on the vehicle which are hinged fit lil'l'rct positions. 'I'hus the Latch is oriented differently relative to the longitudinal, tnisvcr.se and vertical directions ol'the vehicle, depcoding on the type and position oLdoor it retains closecl.

Side c-l r i vcr arid passenger doors of'automobiles are typically hinged at the lions ol'the door, Fitly bloc latch mounted at the rear of the door. In such doors, the latching direction r csp<ds to the transverse direction, and the latch is positicnccl on the door such that the rctcrtii, plate lies in a plane which is parallel to both the transverse and vertical directions.

1; :nmercial vehicle, the rear doors arc mounted within a vehicle frame and hinged at lo sidle. \vith the latch mounted on the door and the striker mounted on the frame. In such vc I,i lest bloc latching direction corresponds to the longitudinal direction and the retention plaice lies in a plane which is parallel to both the longitudinal and vertical directions.

1' the case ol vehicles where the rear door has top mounted hinges, as is the case with the ilgate oi some people carriers and estate vehicles, the latching direction is also in the l,ngiLuctinal direction, but in contrast to the commercial vehicle with side mounted door licks Else arrangement of the latch OH the vehicle is such that the retention plate lies in a Marc which is parallel to both the longitudinal and transverse directions.

11,c present invention is concerned with the problems associated with loads acting parallel lo t1,c retention plate and orthogonally to the latching direction. Such loads are vertical l-cls (its, result of up and down movement between the latch and the striker due to cl.tive movement between the door and the Frame) acting on the latch of both side driver ski sidle lassengcr doors and rear doors of commercial vehicles with side mounted hinges.

I l'wcs!cr. such loads are transverse loads acting on the rear door ol vehicles with top lecl limes.

1 talc above examples, the load on the retention plate results in a bending moment which G;11 cause the retention plate to tail, potentially allowing the latch to unlatch. Thus the Iclt"ition lliOte must be able to withstand certain loads without tailing.

1 n ccl t1csc rctluirenenls, latch manufacturers are increasing the size of retention plate .'cl (libel it can withstanLI a greater bending moment before failure. however increasing the retention Dilate size results in the corresponding striker mounted on the Irame intruding into tlc ELI space ol the vehicle which is not desirable. Furthermore, a larger retention plate 11 s illili,nal weight: to the latch.

Another means of reducing the likelihood of latch failure is to use retention plates made of Trier m;tcrials. I-k-'wever this significantly increases the rnanu-ficturing costs of the 1;1t 13.

A, ,b jcc.t oi'llle present invention is to provide an improved latch.

itcc->rding,! to the present. invention there is provided a latch including a retention plate cIc-l:inh' a plane and slaving a mouth to receive an associated striker and a latch bolt need on the retention plate so as to releasably secure the striker in the latch, the mouth leaving a lrolilc partly defined by a first surface, a second surt'ace and an end surface tanIltUthI" the t'irst and second surfaces, in which one or both of the first and second srl'accs is inclined relative to a latching direction such that engagement between the striker find ogle ol' the first or second surfaces due to a force substantially perpendicular to the l.tchi't, direction and substantially in said plane urges the striker towards the end surt'aee.

I-'lus. since the striker is urged towards the end surface, it is less likely to move away t'rom 1 Cal surl;ace. and theret'ore an increased bending moment is less likely to occur.

I'rct'crahl>. the force substantially perpendicular to the latching direction causes the striker (it move towards the end surl'ace. As the striker moves towards the end surt'ace, the lends nlorllent is reduced thereby l'urther reducing the likelihood of the latch retention 1llLl(w I'ttilii3.

I'lin, 1 the same siz.c latch retention plate, there is less likelihood ol' it failing.

\lfcrv.'tively. [llc latch retention plate can be made smaller with the same failure load, or (lic l)Itile can be maintained at the same size, but using lower strength materials. The use of l<wcr strength natcrials results in reduced material costs, and reduced manu-t:acturing costs as (he material is easier to torm during manut'acture.

Ihc i'lVelition will now be described by way of example oily, with reference to the ccnlanyhah drawings, in which: !;i arc I is a rear view of a commercial vehicle including a latch according to the present inch I]tif) i!.'.Ir(.' 2 is Ài CUt t.\way side view of the vehicle of figure I taken in the direction of arrow C ;lovi! a latch according lo tile present invention, in a latched position, mounted on a rear fluter o-l-'thc velicle ol'-t;gurc 1, I'd arc is an enlarged side view ol'the latch of figure 2, I'i!nr c:l is a.sicle view of a known latch, Ibid ore. is an eulargcd side view of the latch of figure 2 subject to a load, and I'igure (I is an enlarged side view of the latch oi'f'igure 5 showing movement ol'a striker clalive tic the latch \'il '.I'erence to l-;gtre I. there is shown a vehicle, in the form ol'a heavy commercial v.liclc 1). 'I'le vel:icic 1() includes a frame 12 which defines a load space 14 and rear I.,rs ilk Else form ot'a first door 16 and a second door 1X to close off the load space 14. ':I'he lr.it anal second doors 16 1 X are pivotally attached to the frame 12 by hinges 20. Aeeess to II1C law space its achieved by first opening', the first door 16 then opening the second 1oor IX.

/\ l'inrv latcl1 22 is anointed on the first d-,or]6 to engage and releasahly retain a lurid n Hi ry al r iler 24 located on an opposed shut t'ace (not shown) of the second door 1 X. 'I'lle iirsl floor I(i is released by operating a primary release handle 26 which operates the l> i -v I tcl 02.

\ upper licit 2X and a lower latch 30 are mounted on an inside surface 32 of the second Or 18 1roxinatc tl1c top and bottom thcreoi'. 'the upper and Icwer latches 28 3() are c<cctci via a conuccting rod (or cable) 34 (shown schematically in ligurc i) to a sc cutlery r crease handle 36 mounted on the shut taco of the second floor 1 X. corresponding upper striker 38 and a lower striker (not shown) is mounted on a projecting p. ul J.' <>I'lhc flame 12 at the top and bottom ol'the frame opposite the upper and lower l;tclcs 38..(). 'The striker 3X has a striker her 44. l'lle second door 18 is released by bursting flee. secondary rcie.ase handle 36 which unlatches the upper and lower latches.

I'lc upper and lower latches 28,30 are substantially identical and as such only upper latch 2'S \vili be described in cletail.

A, sly I'm figure 2, upper latch 28 includes two retention plates 4G both substantially isle iicl and positioned in spaced apart relationship (shown one behind the other in -figure ::'.. I';cl, ctention plate de-tines a plane (parallel to the plane often paper) and are typically dc l'r: sheet steel.

I.t.cl 28:lirthcr includes a latch bolt, in the form of a claw 48, rotatably mounted between Ihc etc,tion plates on pin S() (see l.'igure 3). The latch includes other components, notably, 1 Our es off tile retention plates (not shown) which hold the retention plates together so as to 1; iicl lishig. 'I'he claw 48 is resiliently biased in a. clockwise direction (when vicin; I'igurc 3) about pin SO to an unlatctling position by a spring (not shown). Each ctetio plate 46 has a mouth 52 defined by a first region 54 and a second region 56. The list region 54 is arranged so as to guide the striker 38 as it approaches the latch. The claw fX Iras a: opc:ing (not shown) for receiving, the striker bar 44. The first region 54 is u-ra' hi such that in the event that the latch 28,30 and the striker her 44 become partly -iis.ligncl (I->r cxa.nple if the hinges wear), the striker 3X is still guided into the mouth 52.

I'lc ski region 56 of the mouth 52 has an upper surface 5X (also known as a t'irst srticc). ;i tower surta.ce (SO (also known as a second surt'ace) and an end surface 62 which cunecis the ripper and lower surfaces so as to define the profile of the second region ol the n,utln 'I'lc upper and lower surfaces 5X,60 are inclined at an angle ol'A degrees relative to ll. INiS \- the axis X being parallel lo a latching direction 1, (see below). In this I,,I>tIilunt iS approximately 5 degrees. In other embodiments this angle can he varied.

1 he seconcl door 18 is latched by moving it in the latching direction L towards the frame 1 ?mntii the claw 4X engages with the striker bar 44. I:.urther movement of the second door 18 ill llic l.ttching direction 1, causes the striker bar 44 to rotate the claw 48 until the claw iclicvL; its liitchcd position, as shown in figure 3, where it its retained by a pawl (not il.;n). ,Ns Ike striker her 44 rotates the claw, the striker bar 44 moves from the first region 11 1) {I]C C,CL(}nL1 region 5(i where it remains when the latch is in the latched position. A c Ic. a'cc (' is proviclecl between a point B on the end surt:ace 62 (defined as the point \,IIC;L bloc end surface coincides with the axis X) and the edge 45 ol the striker bar 44 when il. is in Else latched position, to allow for any excessive movement of the striker beyond the ltcled position as a resmelt ol slamming the second door.

I minlalcl-, the latch, the pawl is moved by the secondary release handle 36, allowing the c line '18 lmotate in a clockwise direction under the action of the spring, and thus release Else striler2X.

t.'uiideration ol figure 5 shows that during c!peration of the vehicle, the vehicle frame may to SLII1jLCI Lo a force E (in this example vertically upwards) which is substantially c'lelicular to the latching direction, and parallel to the plane ofthe retention plates. This tj) I'L'C n.-\Y be tile result of an accident. Since the striker 38 is mounted on the frame 12, the I'(IrC C 1' jS transmitted via the striker bar 44 to the upper surfaces 58 of the retention plates +,. II wit be appreciated that a force in the opposite direction will cause the striker bar 44 t<, ;lLl L)ll tire IOWer surtacc 60 ot the retention plate, and that in certain situations, the force iU.N! lee alternate in direction, thereby moving the striker bar between the upper and lower (;! 1.cc i.

I 1- !,rLL Cycling on the upper or lower surface results in a bending moment M, acting (for Alec salve ill this example) about point B. I i ice! slows a prior art latch under similar circumstances. in this case, the upper and >icr siri.ces l>8 and 16() are parallel to each other and also parallel with the latching (lil'L'Clii,li.

As; rcslt off force F. in this example, the upper surface 158 deforms to the position shown ilk.i.i loftcd lines at 15X'. It can he seen that the position shown at 15X' is angled, by ri,ale ( . relative to the initial position of the upper surface. This deformation can either be :I;'slic delbrnation or plastic det'ormation as a result oLa road accident. As a result of the lel'orcd position of' the upper surface, there is a tendency for the striker bar 144 to move If, Alec right when viewing figure 4, thereby increasing the bending moment M', and i f [CrCiiSin,t', bloc lilelil-'od of complete failure of the retention plate 146.

I'ri to lice embodiment of the present invention shown in figure 5, under similar icrsLuces, upper surface 58 will plastically or elastically deform to the position shown al II\C chain dotted line 5X'. 1-lowever, since the initial Burgle (A) of surface 5X is larger than tI,<:n,le (, >t'initial deformation, then the angle of chain dotted line at 58' is nevertheless siti\c (A-(). As such, there is a tendency for the striker bar 44 to move towards the end l'cc (id (see:tigure h) either prior to any significant deformation taking place or even after T jI; JO jail cleir!rmation has occurred, thereby reducing the bending moment M2.

I'lus it call be seen that by inclining the upper surface 5X (and/or the lower surface), the lc,din moment is reduced Prom known latches, and hence, the latch retention plate can N:itlstad a greater bending moment before failure. Alternatively, to withstand the same lclimnoment, the amount ol' materiel between the mouth and the top and/or bottom ol' lo rcteilic' Plate can he reduced. This enables the projecting part of the frame to be sullen arid hence intrudes less on the access to the load space.

Ike cnbdient of figure 2 shows an upper latch with a force acting as shown. it will be ipl'eciated that the same force will also cause the striker ot'thc lower striker bar to act on the replier srl'ace oftllc lower latch.

11 <, ill al<.' be apprcciatef that a force acting, in the opposite direction will cause the striker laity t, itch <, else lower Surface of the upper and flower latch.

N<,l Plaint its other etnboditnents, the upper and lower latches may be mounted on the frame its <losd to the second door, with the corresponding upper and Lever striker being ri<n.lccl ion Tic second door. In such an embodiment it will he appreciated that a force si.' Else strilcr to act on the upper surface of the embodiment of tenure 2 will cause the !i ilcr Let act or, the lower surface since the latch m-'vcs relative to the striker.

Llc cnt?:,dimcnt ol'I;pure 2 shows a latch with a retention plate having inclined upper and l!\\ic sru-l'ccs. In other embodiments only one ol' the upper or lower surl'aces may be in lineal.

I lc l.;LCI] is ioL restricted to use on commercial vehicle rear doors, and can be used on abler vehicles such as aut.'nlobiles, and other closures such as side passenger doors and i car hoot and tailgate doors. For example, on an automobile side door, a latch mounted on Alec side Assenter door will be subject to a force as indicated in the above embodiments if !l is jn\j(1INICCI in a crash which results in an impact to the vehicle roof'' for example if the lilc rolls onto its roof: Thus in the event of such an impact, the bending moment acrid tile latch is reduced, and thus there is less likelihood of the side doors opening.

Claims (6)

1. Claims 1. A latch including a retention plate defining a plane and having

   a mouth to receive an associated striker and a latch bolt mounted on the retention plate so as to releasably secure the striker in the latch, the mouth having a profile partly defined by a first surface, a second surI; acc and an end surface connecting the first and second surfaces, in which one or both of the first and second surfaces is inclined relative to a latching direction such that engagement between the striker and one ot the first or second surfaces due to a force substantially perpendicular to the latching direction and substantially in said plane urges the striker towards the end surface.
2. 2. A latch according to claim I in which the force causes the striker to move towards the end surface.
3. 3. A latch according to claim] or 2 in which both the first and second surfaces are inclined relative to the latching direction.
4. 4. A latch according to claim 3 in which the first and second surfaces are oppositely inclined.
5. 5. A latch including two retention plates according to any preceding claim, in which the latch bolt is mounted between two retention plates.
6. 6. A vehicle including a closure, a striker, and a latch according to any preceding claim, the latch being mounte 1 on one of the closure or another part of the vehicle, and the striker being mounted on the other of the closure or another part of the vehicle in order to releasably retain the closure in a closed position.