GB2185069A - Demountable hinges - Google Patents

Abstract

A demountable hinge has a hinge pin (3) held captive to a first hinge knuckle (2) by a circlip (6) and releasably held to a second hinge knuckle (12) by a retaining screw (22) threadedly engaged with the second knuckle and having a frusto-conical locking surface (26) which makes a locking engagement with a frusto-conical surfaces (9) on the hinge pin when the retaining screw (22) is tightened. The engagement between the two frusto-conical surfaces (9,26) urges the hinge pin axially of the second leaf to provide a firm engagement between a further frusto-conical surface (10) on the pin and a complementary surface (11) on the second knuckle (12). In the arrangement of Figures 16 to 18 (not shown), in order to reduce the amount by which a door needs to be lifted for demounting, the second knuckle has a cut-out (29) to permit the hinge pin to be disengaged from that knuckle after a reduced axial displacement of the knuckles. <IMAGE>

Description

SPECIFICATION Demountable hinges This invention relates two a demountable hinge primarily, but not exclusively, for a vehicle door.

Demountable hinges are now becoming popular with vehicle manufacturers because they enable the car body with the doors fitted to be painted and then the doors to be removed to provide improved access to the interior of the car body for the installation of other components.

Demountable hinges need to provide accurate realignment of the door when the door is subsequently remounted, and yet the cost of the hinge should, ideally, be little morethanthatofacon- ventional hinge.

Ademountable hinge has been proposed in G.B. A-2 147 655A in whichthe hinge pin isreleasably locked in one hinge knuckle by a plain transverse pin engaging in an arcuate cut-out in a plain cylindrical portion of the hinge pin.

There are various disadvantages with that arrangement. Firstly, since the cylindrical portion of the hinge pin has to be dimensioned to permit its removal there is likely to be some undesirable play between the pin and its mating hinge knuckle. Secondly, the use of an arcuate cut-out in the hinge pin would require the hinge pin to be angularly positioned priorto insertion ofthetransverse pin. Finally, the transverse pin would need to be completely removed to enable demounting of the door.

According to this invention a demountable hinge comprises first and second hinge knuckles, a hinge pin journalled in the first knuckle, means holding captivethe hinge pin to thefirst knuckle againstaxial displacement relative thereto, a part of the hinge pin which projects from the first knuckle being adapted to be received within the eye ofthe second knuckle, said part comprising a portion ofsubstantially frusto-conical shape with the smaller diameter end of the frusto-conical portion being towards the first knuckle, and a threaded locking member adapted to be received in a transverse bore in the second knuckle which breaks into the eye, the threaded locking member having a substantiallyfrustoconical locking surface, and the arrangement being such that when the hinge pin part is within the eye of the second knucklethe locking member can bethreadedlytightened such that a locking engagement is provided between the frusto-conical locking surface ofthe locking member and the frusto-conical portion ofthe hinge pin.

Thus on tightening ofthe locking member a strong wedging engagement can be produced between the frusto-conical locking surface of the locking member andthefrusto-conical surface of said hinge pin por tion, a nd th is engagement can beusedtoreleasably clamp the hinge pin to the second knuckle. The hinge pin can be released simply by unscrewing the locking member, which need not be detached.

The locking surface of the locking member is preferably not precisely frusto:conical but is of concaveconvex shape to increase the surface area of engagement between the locking member and the pin.

The locking member is preferably in the form of a locking screw having a threaded shank.

The shank may receive a threaded nut which abuts with the outside of the second knuckle, or the shank may be threadedly engageable with a com plementarilythreaded portion of said bore in the second knuckle. An enlarged head on the screw provides the locking surface and is provided with a for mation engageable by a tool to enable the locking screw to be screwed in and out of the bore.

The formation is preferably a shaped recess in the screw head, but it may be an external projection or recess in the head in which case it would be arranged that the head projects from the second knuckle.

It will be appreciated that such a locking screw or nut can easily be unscrewed with an appropriate tool to allow the co-operating frusto-conical surfaces to be disengaged to perm it the second knuckle to be removed from the hinge pin, for demounting of a doorfor example.

The locking member may be held captive by suitable means, such as a spring clip,to the second knuckle, or it may be readily removable.

The hinge pin is preferably provided with an abutment surface which is spaced axially from the frustoconical locking surface, faces substantiallytowards the frusto-conical locking surface, and is adapted to engage with a corresponding abutment surface on or in the second knuckle,thearrangementbeing such thatthe abutment surfaces ate pulled into locking engagement bythe co-operation between thefrusto-conical locking surface of the locking member and the frusto-conical surface of the hinge pin portion, which tends to pull the second knuckle axially of the hinge pin.

The abutment surfaces are preferably shaped to provide axial alignment ofthe hinge pin and second knuckle.

Preferably the abutment surface on the hinge pin is a furtherfrusto-conical surface, which opposes the frusto-conical surface of said hinge pin portion to providea generallydiabolo shapetothe hinge pin part. The corresponding abutment surface on the second knuckle then provides a funnel-shaped guide forguiding thefree end ofthe hinge pin into axial alignment with the knuckle bore on remounting the doororotherhinged item.

A demountable vehicle door hinge in accordance with the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure lisa side view ofa first hinge leafand knuckle to which is held captive a hinge pin; Figure2 is a plan viewofthefirst hinge leafand knuckle; Figure 3 is a view looking from the right in Figure 1; Figure4 is a side view of a second hinge leaf and knuckle for attachment to the parts of Figure 1; Figure 5 is a plan view of the second leaf and knuckle of Figure 4; Figure 6is a view looking fromthe right in Figure 4; Figures 7, 8and 9 are enlarged views of the second knuckle corresponding respectively to Figures 5,4 and 6;; Figure 10 is an enlarged side view ofthe hinge pin; Figure 11 is an enlarged side view of a locking screw; Figure 12 is an end view ofthe locking screw looking from the left in Figure 11; Figure 13 is a side view ofthe assembled hinge; Figure 14 is a cross-section on the line 14-14 of Figure 13 showing the co-operation between the securing screw and the hinge pin; Figure 15 is a horizontal section through a car door and pillar showing in plan a modified hinge in accordance with the invention; Figure 76 is a view similarto Figure 4 but of a second leaf having a modified knuckle; Figure 17is a cross-section on the line 17-17 of Figure 16; and Figure 18 is a view looking from the left in Figure 16.

With referenceto Figures 1 to 3 a first hinge leaf 1, which is shown as a flat leaf but could be of any suitable shape to co-operate with a hinged member, is carried by a first knuckle 2 in which is journalled a hinge pin 3, shown in detail in Figure 10. The plain shank4ofthe hinge pin 3 is rotatable in a pairof bushes, such as Pampas (Trade Mark) bushes, indicated at 5 which are secured in opposite ends ofthe bore ofthefirst knuckle 2.

Hinge pin 3 is held captive to the first knuckle 2 by a circlip 6 engaging a recess7 in the upper end ofthe pin 3, a washer 8 being arranged between the circlip 6 and the upper end of knuckle 2. Instead of circlip 6 the pin 3 could be held captive to knuckle 2 in other ways, such as by deformation ofthe end of pin 3, by riveting or by a nut.

The lower part of hinge pin 3 comprises a first substantiallyfrusto-conical portion 9 engaged in use by the locking screw, as will be explained, and a second, opposing, frusto-conical portion 10 which constitutes an abutment surface for engagement with a complementarily shaped abutment surface 11 on the second knuckle 12, shown in Figures4and 7. The pin portion lOterminates at its upper end in an annular shoulder 13 which bears against the underside of the lower bush 5 to bearthe vertical load on the hinge in use.

With reference to Figures 4to 6,the second knuckle 12 carries a second hinge leaf 14which is again for convenience shown as a plain hinge leaf but it could be of any suitable shape.

With the illustrated hinge it is intended that the first leaf 1 be secured to the door pillar, and the second leaf 2 to the door, but if desired the hinge could be inverted and the leaf 1 could instead be secured to the door.

With reference to Figure 8, the bore 15 ofthe second knuckle comprises a plain bore portion 16to which the frusto-conical abutment surface 11 prov ides a counterbore or entrance funnel for guiding the lower end 17 ofthe hinge pin 3 into the bore portion 15on initial assembly of the hinge, and on remounting ofthe doorfollowing demounting.With reference to Figures 7 and 9 the second knuckle 12 is provided with a through bore 1 j' extending transversely to the axis ofthe bore 15which receives the hinge pin and approximatelytangentialthereto. Bore 17' comprises larger and smaller diameter bore portions 18 and 19 respectively connected by a frusto-conical bore portion 20 which breaks through into the bore portion l5forthehingepin,therebyproducinga window 21.The smaller diameter bore portion 19 is threaded.

A locking screw 22, Figures 11 and 12, is adapted to fitwhollywithin the transverse bore 17' releasablyto lockthe hinge pin 3 in bore 15, and t hereby to hold the hinge in an assembled condition. The screw 22 comprises a threaded shank 23 for'threaded engage mentwith the threads of bore portion 19, a head 24 comprising a cylindrical portion 25 adapted to be a rotating fit in bore portion 18, and a frusto-conical portion 26 which provides a frusto-conical locking surface for locking engagement with frusto-conical portion 9 ofthe hinge pin 3which projectsthrough window 21, and is received in use substantially within bore portion 20.

With reference to Figure 10 it will be seen thatthe cone angle of abutment surface 10is 60 , as is that of the complementary surface 11,this angle being chosen to avoid a wedging action between those surfaces that would make it difficu It to release the pin 3 from the second knuckle 12 for demounting thevehicle door. In general an angle in the range substanti ally 50"to substantially 65" would be suitable.

The mounting of the second leaf 14to the first leaf 1, knuckle2 and pin 3, assembled as in Figure 1,to bring the leaves to the assembled condition of Figure 13, is accomplished by dropping the second knuckle 12 overthe upper end 17 of pin 3, this being assisted bytheshapeofsurface 11 and by a small chamfer27 on the pin 3. The locking screw 22 isthen screwed into the transverse bore 17' by means of a key engageable with a hexagon socket 28, or socket of other suitable shape, provided in the screw head 24, the threads of shank 23 co-operating with those of bore portion 19. Alternatively the head 24 could be made longer so that it projects from the bore 17', and the external surface of the head could be provided with projections or recesses for engagement by a suitable tool.This screwing action brings the locking surface 26 into engagement with the surface 9 ofthe pin, so that on further tightening ofthe screw 22 the co-operation between su rfaces 26 and 9 tends to drawtheknuckle 12 downwards on pin 3 andforces abutment surface 10on the pin more firmly against surface 11, and the pin 3 will be urged transversely in bore portion l6tolockthepin3tothesecond knuckle 12.

In orderto increase the surface of engagement between the surfaces 26 and 9 the surface 9 is not preciselyfrusto-conical, but is made as a concavo convex surface, the concavity being indicated in Figure 10 by the radius of curvature R.

In a modification, not shown, the shank 23 ofthe locking screw 22 is extended, and the extension is adapted to receive a spring clip which holds captive the screw 22 to the second knuckle 12, yet permits sufficient unscrewing ofthe screw 22 to permit removal ofthe hinge pin 3.

In a further modification, not shown, the shank 23 is extended to receive a nut and no threads are prov ided on the bore portion 19, the nut being used to tighten the member 22 to the pin 3.

In yetafurther modification, notshown,the locking screw 22 of Figure 11 is threadedly en gageablewith a nut, and the bore 17' is madesufficiently large to enable the nutto be axiallyslidable therein and to abut with the pin 3.

Preferably the nut is provided with a frusto-conical locking surface similarto surface 26 so that the surface 9 ofthe pin is engaged both by the frusto-conical locking surface on the screw 22 and by that on the nut. In this case the bore 17' and the external surface ofthe nutorofthescrewhead 25would becom plementarily shaped to hold the nut or the screw respectively against rotation relative to the second knuckle 12. Forexample, the bore 17' could beof hexagonal cross-section.

With some cars lifting ofafrontdoortodemount the door is severely restricted by the shape ofthe car wing. In orderto reduce the amount by which itis necessaryto lift the doorto disengagethesecond knuckle from the hinge pin of the upper hinge ofthe front door, the second knuckle of the upper hinge is provided in its side with a cut-out which breaks into the hinge pin bore ofthe second knuckle. Figures 16 to 18 show such a modified second knuckle for use in the hinge of Figure 13, the knuckle 12 having been cut-away on one side for the depth D.The cut-out 29 is defined between a surface 30 which is transverse to the axis of bore 15, a surface 31 which includes the axis of bore 15 and is co-planarwith one surface of leaf 14, and a surface 32 which extends parallel to the axis of bore 15 and normal to the plane ofthe leaf 14.

In orderto remove a doorwhich is mounted on a pairof hinges ofthetypeshown in Figure 13, but in which the upper hinge is modified as in Figures 16to 18, it is necessary to release the locking screws 22 of both hinges, and liftthe door sufficiently forthe hingepinsoftheupperhingeto pass beneaththe surface 30, so that the leaves of the upper hinge can be disconnected by tilting of the upper part ofthe door outwards from the door pillar, this tilting being accommodated by the shape of the hinge pin, Figure 10, ofthe lower hinge.

Whilstthe cut-out 29 permits disconnection ofthe leaves without substantial relative axial movement ofthe leaves of the upper hinge, the presence ofthe cut-out 29 affects very little the clamping action of the screw 22 on the hinge pin because the cut-out is positioned such that the screw 22 is holding the hinge pin against surfaces ofthe knuckle 12 that have not been disturbed in generating the cut-out.

Depending upon which way round the hinges are mounted it may in some cases be necessary to lower a door in orderto detach it, and in some cars the use of a cut-out knuckle may then be required on the lower hinge to prevent the bottom ofthe doorfoul ing the body work, before the leaves of the lower leaf have been disconnected.

Figure 15 shows a modification of the hinge of Fig ures 1 to 12 in which the leaf 14 is crankedforsecur ing to a door pillar33, the leaf 1 being secured within door 34. The direction of the transverse bore 17' in leaf 2 is chosen to permit a tool to clear pillar corner 35 when the door is opened.

The hinges described are capable ofwithstanding the current standard strength tests, yet enable rapid demounting of a vehicle door, and quick remounting of the door whilst preserving the axial alignment of the hinge pin 3 and knuckle 12 in the assembled hinge.

Claims (9)

1. Ademountablehingecomprisingfirstand second hinge knuckles, a hinge pin journalled in the first knuckle, means holding captive the hinge pinto the first knuckle against axial displacement relative thereto, a part of the hinge pin which projects from the first knuckle being adapted to be received within the eye ofthe second knuckle, and a locking member adapted to be received in a transverse bore in the second knuckle which breaks into the eye, said part comprising a portion of substantiallyfrusto-conical shape with the smaller diameter epd ofthefrusto- conical portion being towards the first knuckle, the threaded locking member having a substantially frusto-conical locking surface, and the arrangement being such that when the hinge pin part is within the eye of the second knuckle the locking member can be threadedlytightened such that a locking engagement is provided between the frusto-conical locking surface ofthe locking member and the frusto-conical portion ofthe hinge pin.

2. A hinge as claimed in Claim 1 in which the locking surface of the locking member is of concave convex shape to increase the surfåce area of engage- ment between the locking member and the pin.

3. A hinge as claimed in Claim 1 or Claim 2 in which the locking member is in theform of a locking screw having a threaded shank.

4. A hinge as claimed in anyofthe preceding claims in which the hinge pin is provided with an abutment surface which is spaced axially from the frusto-conical locking surface, faces substantially to wards the frusto-conical locking surface, and is adap- ted to engage with a corresponding abutment surface on or in the second knuckle, the arrangement being such that the abutment surfaces are pulled into locking engagement by the co-operation between thefrusto-conical locking surface ofthe locking member and the frusto-conical surface of the hinge pin portion.

5. A hinge as claimed in Claim 4 in which the abutment surface on the hinge pin is a furtherfrustoconical surface, which opposes thefrusto-conical surface of said hinge pin portion to provide a gener allydiaboloshapetothehingepin part.

6. A hinge as claimed in anyofthe preceding claims in which the second knuckle is provided with a cut-out which extends transversely into the hinge pin bore ofthe second knuckle and which enables the hinge pin to be disengaged from the second knuckle by passing transversely of the hinge pin bore through the cut-out, the cut-out extending from that end of the second knuckle which is adjacent to the first knuckleto enable the hinge pin two be released from the second knuckle when the knuckles have been separated axially by less than the axial length of the second knuckle.

7. A demountable hinge substantially as described with reference to Figures 1 to l4oftheac- companying drawings.

8. A hinge as claimed in claim 7 but modified substantially as described with reference to Figures 16 to 18 ofthe accompanying drawings.

9. Avehicle in which a door ofthe vehicle is connected to the vehicle structure by at least one hinge in accordance with any of the preceding claims.