GB2327703A - Securing cylinder lock connecting bars - Google Patents

Abstract

A method of securing a connecting bar (16a) to an end of a plug (11) of a cylinder lock (10) comprises providing in an external annular groove (14) at the end of the plug, a retaining ring (15) which has a pair of diametrically opposed ears (18, 19) extending into a diametral slot (17) extending inwards from the end of the plug, and inserting a head (20) of the connecting bar (16a) into the slot so as to deform one of the ears and be snap-fittingly received into said slot (17) and thereby secured to the plug. The head of the connecting bar has a chamfered leading surface to engage said one ear and an arcuate recess behind the head to receive the other ear to allow the head to be moved angularly as it is inserted into the slot (17) as a snap-fit. The invention also relates to a cylinder lock produced by the method and to a connecting bar for use therewith.

Description

IMPROVEMENTS RELATING TO CYLINDER LOCKS This invention relates to improvements relating to cylinder locks, and in particular concerns a cylinder lock of the type where a connecting member, normally a flat bar, extends from the inner end of the rotatable plug of the cylinder lock, the connecting member being arranged, in use, to actuate the latch bolt/dead bolt of a locking mechanism controlled by the cylinder lock.

With a cylinder lock of this type it is necessary to ensure that the plug cannot be axially withdrawn from its cylinder in either direction when a correct key is inserted, at least in order to prevent the pins possibly becoming lost. At the front end of the lock, the plug is retained against inwards axial movement by a flange on the plug being received in an enlarged recess at the end of the bore through the cylinder in which the plug is received.

At the rear end of the lock, inwards axial movement of the plug is prevented by a plug retaining ring engaged in an annular groove in the periphery of a part of the plug protruding from the end of the cylinder, the ring having an outer diameter which is greater than the diameter of the normal bore in the cylinder, so that any inwards force on the plug results in the ring engaging against the rear end of the cylinder.

The retaining ring has two diametrically opposed, inwardly facing ears which are received in a diametral slot through the end of the plug. This retaining ring is of deformable material and is supplied in an 'openedout' form for placing in position at the groove in the plug and then being 'crushed' to close it up and tightly engage in the groove with its ears received at opposite ends of the plug slot which communicates with the external annular groove.

As described, a connecting member extends from the inner end of the plug, and this is conveniently secured to the plug by use of the retaining ring. The connecting member is, as mentioned, normally a flat bar, and this bar has a pair of symmetrically arranged, identical grooves cut in its respective narrow longer sides adjacent one of its ends, thereby, in effect, providing a head at said end. Prior to the 'closing-up' of the retaining ring, this head is disposed within the slot at the end of the plug with the longitudinally aligned grooves in the bar arranged at the axial position of the groove in the periphery of the plug. Accordingly when the retaining ring is 'crushed' to close it down, the ears of the ring move into the plug slot and also into the respective grooves in the bar, thereby to retain the head of the bar behind the ears and thus to secure the bar to the plug. The thickness of the bar is slightly less than the width of the plug slot, but the bar is firmly engaged.

Since the retaining ring must be 'crushed' to retain the plug in the cylinder, and is thus engaged in the plug groove as part of the process of assembly of the plug, an assembled cylinder lock as packaged by a manufacturer must inciude the attached connecting bar. It will however be appreciated that the provision of the connecting bar makes packing somewhat cumbersome, with the attendant possibility of the packaging being ripped or pierced by the end of the bar.

An object of the invention is to reduce or overcome this disadvantage.

According to a first aspect of the invention there is provided a method of securing an elongate element at an end of a plug of a cylinder lock, which end protrudes from the cylinder of the lock, said end of the plug having an at least part-annular external groove, a plug retainer held in said groove and having retention means extending into a slot in said end of the plug which communicates with said groove, said elongate element having a head defined at one side of recess means in the periphery of said elongate element, the method comprising inserting said head into said slot in said end of the plug so that it is received past said retention means as a snap-fit, with the retention means being received in said recess means to secure the elongate element to said plug.

Preferably a leading surface of the head is chamfered/bevelled to allow the element to snap-fit past a flexible ear of said retaining ring constituting said retention means.

According to a further aspect of the invention, there is provided a cylinder lock in which an elongate element has been secured thereto by means of said method of the invention.

According to a still further aspect of the invention there is provided an elongate element for securement at an end of a plug of a cylinder lock, which end protrudes from the cylinder of the lock, said end of the plug having an at least part-annular external groove, a plug retainer held in said groove and having retention means extending into a slot in said end of the plug which communicates with said groove, said elongate element having a head defined at one side of recess means in the periphery of the element, and a leading surface of said head being bevelled/chamfered, so that, in use, upon insertion of the head into said slot, said leading surface engages said retention means and the head moves past said retention means to snap-fittingly engage with said plug.

Preferably the recess means are longitudinally aligned recesses in respective opposite longitudinal side surfaces of the element, one recess having an arcuate surface to allow one part of the head to be hooked over one ear forming said retention means and the element moved angularly to bring said leading surface of the head into engagement with another ear forming said retention means. Conveniently the other recess, which is adjacent said leading surface, has a sloping surface. The recesses join the head at respective shoulders which prevent release of the secured element by engagement against said retention means upon any attempted movement outwards of said plug.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic side view of a cylinder lock showing how a plug thereof is retained in its cylinder against axial movement, and showing a connecting bar extending from a protruding end of the plug, Figure 2 is a sectional view on line 2-2 of Figure 1, with the connecting bar not shown, Figures 3 and 4 are respectively enlarged plan and side views of a plug retaining ring shown in Figures 1 and 2, but here in an opened-out state, Figure 5 is an enlarged plan view of the connecting bar of Figure 1 according to the invention, and Figures 6 and 7 schematically show the method of the invention for securing the connecting bar of Figure 5 to the plug of the cylinder lock.

Figure 1 shows a cylinder lock 10 of the type referred to above, where the rotatable plug 11 of the lock is retained in its associated cylinder 12 against axial movement in either direction. As shown in Figure 1, the front of the plug is formed with an annular flange 13 received in a corresponding annular recess in the front end of the cylinder, this recess being in communication with the normal bore through the cylinder in which the plug is received. The inner surface of the recess thus constitutes an annular shoulder against which the flange engages to resist attempted inward axial movement from said front end of the cylinder lock.

At the other end of the lock, the plug protrudes slightly from the end of the cylinder and is formed with an external annular groove 14 in which is fitted, in a manner to be described, a split retaining ring 15. This ring, as shown in Figure 1, has an outer diameter which is greater than the diameter of the normal bore through the cylinder so that any axial inwards force on the plug at this end of the lock results in the ring engaging against the rear end of the cylinder and thus preventing the plug being pushed out of the cylinder at its front end. Figure 1 also shows a connecting bar 16 which, as will be described, is secured to the plug and extends therefrom. In use this bar extends to a locking mechanism associated with the cylinder lock, so that rotation of the plug results in corresponding rotation of the bar which then is translated at the locking mechanism in the corresponding movement of either a latch bolt, a dead bolt, or some other component of the locking mechanism as required.

Figure 2 shows how the end of the plug has a diametral slot 1 7 extending some way into it in an axial plane. As will be described, the width of this slot is slightly greater than the thickness of the connecting bar 16, an end of the bar being received in said slot to form the connection between the plug and the bar so that rotation of the plug is translated into corresponding rotation of the bar.

The ring 15 is shown in detail in Figures 3 and 4, in an 'opened-out' condition. The material of the ring is such that the ring is deformable in its own plane, so that by the use of a suitable tool the ring can be 'closed-up' into the form of a split annul us given that, as shown in Figures 3 and 4, the opened-out ring is non-circular. As will be appreciated from a comparison of Figures 2 and 3, the 'closing-up' of the ring 15 brings into diametral opposition a pair of ears 18, 19 respectively formed integrally on the inside of the ring 15, each ear being sized so that, as shown in Figure 2, it can extend into the slot 1 7 when the ring is engaged on the plug and 'closed-up'.

A conventional connecting bar is of generally constant rectangular shape in plan and also of rectangular cross-section, having a T-shaped end.

Alternatively the end can be generally T-shaped, with, adjacent one end, the opposite narrower longitudinal side surfaces of the bar being formed with a pair of respective non-arcuate recesses, the end of the bar beyond said recesses thereby being formed as a head with respective flat shoulder surfaces being defined at the junction between each recess and the head. The recesses are identical and axially aligned so that the bar has a longitudinal axis of symmetry. In use the end of the bar is inserted into the slot 1 7 so that the recesses are axially aligned with the external groove 14 in the periphery of the plug. The ring 15 is then positioned around the plug at the groove 14 and 'closed-up' by 'crushing' the free ends of the ring towards one another so as to form the ring into a truly circular shape as shown in Figure 2 with the respective ears 18, 19 being moved into respective opposite ends of the slot 1 7 and also into the respective recesses in the bar, directly behind the head. When the 'closing-down' of the ring into its Figure 2 state is complete, it will be appreciated that the bar will now be secured to the plug in that any attempted outward axial movement of the bar will cause the shoulder surfaces of the head to engage against the ears, whereby since the ring is retained within the groove in the plug, such outward movement of the bar is prevented.

As previously mentioned, the assembled form of a known cylinder lock, namely the state in which it is sold, includes the connecting bar attached to the plug as described, this being disadvantageous as regards the packaging of such assembled cylinder locks, since the projecting bar can damage such packaging. It will also be appreciated that a larger size of packaging is required to accommodate the extending bar than would be the case if the assembled cylinder lock without such bar attached were being packaged.

The present invention addresses this problem by enabling the bar to be fitted to an assembled cylinder lock when required, rather than at the time of assembly of the plug and cylinder together, thereby facilitating packaging.

To permit the connecting bar to be attached to the plug after the cylinder lock assembly between the plug and the cylinder has been completed, the head of the connecting bar is shaped to enable the end of the bar at which the head is formed to be snapped-in to the plug slot and thereafter, as before, retained in place by the ears of the retaining ring engaging in respective associated grooves in opposite longitudinal side faces of the bar. However as will be described, in one embodiment, the head and recesses are sized and shaped differently from the known form of connecting bar so as to facilitate the snap-fit assembly process.

Figure 5 shows a connecting bar 1 6a of one embodiment of the present invention. This has substantially the same form as the connecting bar 16, but has a head portion 20 at its one end which is of greater lateral extent than the remainder of the bar and which has respective recesses 21, 22 in its opposite longitudinal sides 23, 24 of a different form to the recesses, or equivalent, behind the head of a conventional connecting bar.

The head portion 20 at one side of the recesses 21, 22, is of generally rectangular form with its longer sides being normal to the length of the bar and extending laterally beyond the sides 23, 24. The recess 21 in the side 23 is formed with a straight inwardly sloping surface 25 which extends to an undersurface 26 of the rectangular head portion 20, whilst the recess 22 in the side 24 is generally semi-circular, the surface 27 of recess 22 joining the head portion at a further undersurface 28 which can be regarded as a continuation of the undersurface 26, which undersurfaces together form part of the one longer side of the rectangular head portion 20. The two recesses 21, 22 are generally aligned longitudinally of the bar, although the recess 21 extends for a somewhat greater length along the bar. The outer longer side of the rectangular head portion 20 is formed with a chamfered surface 29 which thus forms an edge of the head portion leading to the undersurface 26. Finally with regard to Figure 5 it will be noted that the position of the head portion 20 relative to a central longitudinal axis of the bar is such that it is slightly offset so that a greater part of the head projects to the right of the centre line.

To connect the bar of Figure 5 to a plug of an assembled cylinder lock, for example as shown in Figure 2, the projecting part of the head adjacent the recess 22, which is in the form of a hook, is inserted into the slot 1 7 so that this hook engages behind an ear, for example the lower ear shown in Figure 2, of the retaining ring. This position is shown in Figure 6. The engagement of the ear in the curved recess 22 enables the bar to be, in effect, moved angularly relative to the plug so that it is possible to pivot the bar from the Figure 6 position so that the chamfered surface 29 at the leading edge of the head portion 20 is brought into engagement with the other, in this case upper, ear of the retaining ring. The material of the ring and the resiliency of the ears is such that upon the chamfered surface engaging said ear, it is possible gently to push/pivot the bar further into the slot so that the ear engaged by the surface 29 is locally deformed to allow passage of the head portion 20 fully into the slot 17, whereupon the whole of the head portion then lies within the plug behind the ears 18, 19 which are now received in the recesses 21, 22 respectively adjacent the undersurfaces 26, 27. This snapped-in position of the bar is shown in Figure 7 and from this it will be appreciated that the bar is now securely connected to the plug, in that any attempt to pull the bar outwardly will result in engagement of the respective undersurfaces 26, 28 against the fixed ears 18, 19 on the retaining ring which is secured to the plug by virtue of being received in the groove 14.

Accordingly, in one embodiment, without changing the form of the already known retaining ring it is possible to overcome the packaging problem referred to by removing the need to secure the connecting bar to the plug at the same time as engaging the retaining ring on the plug.

Although the presently used known ring was not intended for use in a snap-fit assembly as described, it is believed that the degree of flexibility of its ears will be sufficient for the snap-fit to take place.

The shape of the end of the connecting bar shown in Figure 5 has been designed to provide maximum strength, so that the shoulder does not bend when the bar is inserted into the plug. It may be possible to use other shapes, such as arcuate, but it may result in a weaker bar. A standard bar, has, in one form as described, no arcs, being T-shaped at its end.

Instead of only one side of the head being chamfered, both sides could be of such form. However this may be disadvantageous in encouraging 'straight' insertion, which would require both ears of the ring together to be sufficiently resilient.

It will be appreciated that various other configurations at the end of the connecting bar could be adopted to provide this snap-in connection so that the recesses need not be in the forms described and illustrated, and indeed it may be possible to use the same recesses as with a known connecting bar. Moreover a laterally enlarged head portion need not be essential and some other shape may be possible for the leading surface of the head portion which engages an ear of the retaining ring. It will also be appreciated that it may be possible for part of the head portion 20 to be resilient instead of the ear which it engages in order to provide the snap fit, or both of the engaging parts may have some resilience to allow the same effect.

In another embodiment, the retaining ring could be of springy material, so that it is snapped into position in the plug groove. Both ears would thus be highly resilient, and accordingly the shape of the leading surface of the head of the bar could be different from that shown, whilst still enabling the snap-fit to be effected.

Claims (18)

1. A method of securing an elongate element at an end of a plug of a cylinder lock, which end protrudes from the cylinder of the lock, said end of the plug having an at least part-annular external groove, a plug retainer held in said groove and having retention means extending into a slot in said end of the plug which communicates with said groove, said elongate element having a head defined at one side of recess means in the periphery of said elongate element, the method comprising inserting said head into said slot in said end of the plug so that it is received past said retention means as a snap-fit, with the retention means being received in said recess means to secure the elongate element to said plug.

2. A method as claimed in Claim 1, wherein the plug retainer is in the form of a retaining ring having at least one projection forming said retention means, the head portion snap-fitting past said projection upon insertion of the head into said slot.

3. A method as claimed in Claim 1, wherein the plug retainer held in said groove is in the form of a retaining ring having two diametrically opposed ears which form said retention means extending into said slot, the head portion snap-fittingly engaging past at least one of the ears upon insertion of the head into the slot.

4. A method as claimed in Claim 3, comprising initially inserting said head partly into said slot so that one of said ears is received in said recess means, and then moving said elongate element angularly so that the head snap-fits past said other of the ears to be received fully in said slot.

5. A method as claimed in any one of the preceding claims, wherein the plug retainer having said retention means is of springy material and is thus snapped into position in said groove of the plug.

6. A method as claimed in Claim 5, wherein the plug retainer is a retaining ring having two diametrically opposed ears forming the retention means, said ears being received in said slot as the ring is snapped into said groove.

7. A method as claimed in any one of the preceding claims, comprising deformation of the retention means by said head upon insertion thereof.

8. A method as claimed in any one of the preceding claims, wherein a chamfered surface of the head engages the retention means as it is inserted into said slot.

9. A cylinder lock having an elongate element secured at an end of a plug thereof by a method as claimed in any one of the preceding claims.

10. An elongate element for securement at an end of a plug of a cylinder lock, which end protrudes from the cylinder of the lock, said end of the plug having an at least part-annular external groove, a plug retainer held in said groove and having retention means extending into a slot in said end of the plug which communicates with said groove, said elongate element having a head defined at one side of recess means in the periphery of the element and a leading surface of said head being bevelled/chamfered, so that, in user, upon insertion of the head into said slot, said leading surface engages said retention means and the head moves past said retention means to snap-fittingly engage with said plug.

11. An element as claimed in Claim 10, wherein the recess means are longitudinally aligned recesses in respective opposite longitudinal side surfaces of the element.

12. An element as claimed in Claim 11, wherein one recess has an arcuate surface to allow one part of the head to be hooked over one part of said retention means and the element moved angularly to bring said leading surface of the head into engagement with another part of said retention means.

13. An element as claimed in Claim 11 or Claim 12, wherein a recess or said other recess is adjacent said leading surface and has a sloping surface.

14. An element as claimed in any one of Claims 11 to 13, wherein the recesses join the head at respective shoulders which prevent release of the secured element by engagement against said retention means upon any attempted movement outwards of said plug.

15. An element as claimed in any one of Claims 10 to 14, wherein said head extends laterally beyond a longitudinally extending body part of the element.

16. A method of securing an elongate element at an end of a plug of a cylinder lock, substantially as hereinbefore described.

17. A cylinder lock substantially as hereinbefore described, with reference to, and as shown in the accompanying drawings.

18. An elongate element for securement at an end of a plug of a cylinder lock, substantially as hereinbefore described, with reference to, and as shown in Figures 5 to 7 of the accompanying drawings.