GB2145763A - Locks - Google Patents

Abstract

The deadbolt 2 of a rim lock can normally be withdrawn from the inside by turning the knob 7. By key-operation of a cylinder 43 carried within the knob, however, the knob can be locked from the inside to prevent potential intrusion by a burglar breaking out glass from an adjacent window or glazed door for example, and reaching in to turn the knob. The knob is journalled in the lockcase 1 with a limited degree of axial freedom. In its normal axial position shown in Fig. 9 the knob turns freely and is located axially by a radial tongue 50 running between a shoulder 53 of the lockcase and a retaining plate 23. When the key is inserted to turn the cylinder plug 43 within the knob, the tongue 50 is withdrawn by an eccentric peg 48 on the rear of the plug 43. The knob can now be pushed in as a whole against the action of a return spring 57, so that projections 54 on the knob engage in recesses 56 in a surrounding skirt 55 of the lockcase to securely resist turning of the knob. Turning back the cylinder plug 43 within the knob while the knob is pressed in projects the tongue 53 behind the plate 23 in the lockcase to retain the knob in its locked position. Any forcing torque applied to the knob is now resisted by the robust formations 54/56 without putting any load upon the tongue 50. <IMAGE>

Description

SPECIFICATION Locks The present invention relates to locks and in one aspect is concerned to provide a keyoperated mechanism for selectively preventing the rotation of a turn knob, lever handle or the like manually operable member provided to withdraw the bolt of a door lock. Particularly, though not exclusively, the invention relates to a mechanism of this nature as applied to a so-called rim nightlatch.

It is well known to provide a nightlatch with a mechanism of the above-indicated character, the purpose being to eliminate the risk that the associated door might be opened by an intruder breaking out a small piece of door glass (in the case of a glazed door), or of an adjacent window, and reaching in to turn the knob or like member. A typical prior art mechanism is shown in UK patent specification No 687223 where a cylinder locking mechanism is incorporated in the knob and, when operated by a key from the inside, moves an abutment from the knob into a recess formed in the lockcase to block the rotation of the knob.The strength of the relatively small knob-locking abutments typified by specification No 687223 may not, however, be sufficient to resist a determined attempt to force the locked knob, and one of the aims of the present invention is to provide a knob-locking mechanism which is more suited to the provision of a high-strength locking connection between the knob and lockcase.

The invention accordingly resides in a lock comprising a turn knob, lever handle or the like manually-operable member (referred to herein, for convenience, as a "knob") rotatably mounted with respect to a lockcase for withdrawing a bolt of the lock; the knob also being capable of limited axial displacement between first and second positions respectively outward and inward with respect to the lockcase; the lockcase and knob having complementary formations which, when the knob is in its said second axial position, engage together to block rotation of the knob but which, when the knob is in its said first axial position, disengage to permit rotation of the knob for withdrawing said bolt; a key-operated cylinder mechanism incorporated in the knob and being rotatable and axially displaceable as a whole therewith; the cylinder mechanism comprising a plug normally locked against rotation relative to the knob but being rotatable relative to the knob by a correct key, and an abutment member normally extending transversely from the cylinder mechanism but being movable to a withdrawn position by rotation of the plug relative to the knob; with the knob in its first axial position and the abutment member in its extended position the abutment member permitting rotation of the knob but blocking displacement of the knob to its second axial position; and with the knob in its second axial position and the abutment member in its extended position the abutment member blocking displacement of the knob to its first axial position, thereby to maintain said complementary formations in engagement to block rotation of the knob; displacement of the knob between its first and second axial positions thus requiring rotation of the cylinder plug relative to the knob to withdraw the abutment member, In a lock according to the invention it is the complementary formations on the lockcase and knob which resist turning of the knob in its said second axial position and considerable freedom of design choice is available in the positioning and shaping of these formations to achieve a high-strength connection.In one preferred embodiment the lockcase comprises an annular skirt portion extending outwardly from the body of the case and encircling a shank portion of the knob, the outer end of this skirt presenting one or more axially-facing recesses or projections, and a portion of the knob presenting one or more complementary projections or recesses which face and remain spaced from the recesses or projections of the skirt while the knob is in its said first axial position and which engage therewith when the knob is in its said second axial position.

It is of note that in a lock according to the invention the aforesaid abutment member is provided essentially to maintain the relative axial location of the knob and lockcase and need not itself serve to resist any torque loading if an attempt is made to force the knob while locked in its second axial position.

By this abutment member serving, when extended, also to block movement of the knob from its first to its second axial position it is ensured that the knob cannot accidentally or inadvertently become locked during normal manipulation or at any other time without the use of a correct key. A further advantage of the above defined mechanism is that the axial position adopted by the knob at any time can serve to indicate at a glance whether it is in its locked or free condition.

These and other aspects of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a plan view of a lockset in accordance with the invention, as fitted to an entrance door; Figure 2 is a view of the lockset taken in the direction of arrow 'A' in Figure 1, with the staple omitted and the external cylinder withdrawn; Figure 3 is a view of the lockset taken in the direction of arrow 'B' in Figure 1; Figure 4 is a view of a mounting plate for the lockcase taken in the direction of arrow 'B' in Figure 1; Figure 5 is a view of the mechanisn within the lock case taken in the direction of arrow 'C' in Figure 1; Figures 6 and 7 are partial views of the snib and main bolt of the lock mechanism in two different operative conditions, taken in the direction of arrow 'D' in Figure 5;; Figure 8 is a rear view of the internal operating knob of the lockset with a retaining cap removed; and Figure 9 is a section through the knob and associated components taken on the line 'EE' in Figure 8.

The lockset shown in Figures 1-3 is of the style commonly referred to as a rim nightlatch, locks of this style being popular for fitting eg to the main entrance doors of private dwellings. It comprises a case 1 surface mounted to the inside of the door D and from which the head of a main bolt 2 protrudes to engage in the box 3 of an associated staple 4 fixed to the door frame F. From the outside the bolt can be withdrawn by operation of a correct key 5 (Fig 2) in a cylinder 6 and from the inside the bolt can normally be withdrawn simply by turning a knob 7 borne by the case 1, without any key-operation.

The components of the lockset are secured to the door in a manner which is common for this style of lock. That is to say the outside cylinder 6 is located in a bore 8 prepared in the door and is clamped in place by means of connecting bolts 9 extending from a plate 10 (shown in Figure 4) which is screwed to the inside face of the door. The lockcase 1 is clipped and screwed (as at 11) to the aforesaid plate, and is further secured by screws passing directly into the door edge through holes 1 2 in the forend of the case.

Figure 5 shows the arrangement of parts within the lockcase 1. The main bolt comprises the rectangular block-like head 2 to which is riveted an apertured, plate-like tail 1 3 borne for rectilinear motion by guide surfaces cast in the case 1. The bolt is sprung outwardly by a main spring 14 which engages behind the head 2. Associated with this bolt is a dog or locking lever 1 5 pivoted on a pin 1 6 and urged in the anti-clockwise sense (as viewed in Figure 5) by a spring 1 7. The lever 1 5 has a head portion formed with a series of ratchet teeth 1 8 which engage with complementary teeth 1 9 on the top of the bolt tail 1 3 so as normally to deadlock the bolt in its extended condition.Rearwardly of this head portion the lever 1 5 bifurcates into two parallel legs (of which only one is seen in Figure 5) straddling the tail 1 3 and each terminating in an out-turned flange 20. By providing a plurality of interengageable teeth 18/19 on the locking lever and bolt tail it can be ensured that the bolt will deadlock at a plurality of discrete positions, not just at its fully-extended position, to afford security aqainst sprinqinq back the bolt even if for some reason it has not extended fully.

A cam 21 is keyed to the inner end of the knob 7 by two opposed flats 22 (and by the member 50 to be described hereinafter) and is located in the axial sense by an apertured retainer plate 23 screwed to the inside of the case 1. The cam 21 has a circumferential notch-not seen in Figure 5 but located immediately behind the notch 24 shown in the retainer 23-in which the flange 20 on the lever leg to the far side of the tail 1 3 (as viewed in Figure 5) normally sits. The cam 21 also carries a peg 25 which in the position of Figure 5 is spaced slightly from the rear edge 26 of the bolt tail aperture.By turning the knob 7 and cam 21 in the anticlockwise sense (as viewed in Figure 5) the relevant flange 20 is driven out of the aforesaid cam notch to pivot the lever 1 5 so that its teeth 18 disengage from the teeth 1 9 of the bolt tail, and the peg 25 then comes into contact with the edge 26 so that continued rotation of the knob (through a total of about 90') withdraws the main bolt into the lockcase. A return spring (59 shown in Figure 9) acting on the knob via the cam 21 returns the knob to its starting position when released. In order to withdraw the bolt from the outside a second cam 27 is provided, being rotatably mounted on the plate 10 as shown in Figure 4.An opening 28 in this cam receives a drive bar 29 (Figure 2) extending from the cylinder 6 so that as the plug of this cylinder is rotated by the key 5 the cam 27 is also turned. The cam 27 has a notch 30 in which the nearer flange 20 (as viewed in Figure 5) normally sits, and a peg 31 which works on the upper part of the bolt tail surface 26 to withdraw the bolt after the flange 20 has been driven out of the notch 30 to release the deadlocking.

After any withdrawal of the main bolt by either the knob 7 or key 5 to permit opening! of the door D the bolt is initially latched in its withdrawn position by means of a snib 32, the form of which is more clearly seen in Figures 6 and 7. This element is pivoted in the forend of the lockcase and has a head 33 which in the position of Figure 6 protrudes out of the forend below the main bolt head 2 (as the lock is oriented in Figures 2 and 5). A spring 34 biases the snib in the clockwise sense (as viewed in Figures 6 and 7). When the main bolt is extended the snib 32 adopts the position of Figure 7, in which it is retained by its tail portion 35 engaging the adjacent flank of the bolt tail 1 3. As the bolt is withdrawn and the door opened, however, the snib is released to pivot under its spring bias to the position of Figure 6, in which its tail 35 now intercepts a displaced portion 36 towards the lower edge of the bolt tail, to retain the bolt withdrawn. The depth of the box 3 in the staple 4 (Figures 1 and 3) is such as onlv tn accommodate the main bolt head 2.Conse quently, when the door is closed again the arcuate surface of the snib head 33 strikes the edge 37 of the staple and is forced back to its Figure 7 position, thereby releasing the main bolt to shoot forward again into the box 3 under the action of its spring 14, whence it is deadlocked by the lever 1 5. Having regard to the shape of the bolt head 2 and the automatic deadlocking action of the lever 15, it will be appreciated that the function of the snib 32 as described above is such as to allow the door to be closed by a slam action, ie to avoid the necessity of withdrawing the bolt by hand each time the door is to be closed.

If the user should wish to latch back the main bolt for a period independently of the operation of the snib 32, the bolt is withdrawn to its fullest extent by use of the knob 7 and a button 37 in the lockcase is pressed in against a bias spring 38 so that upon release of the knob a tang 39 on the lower edge of the bolt tail 1 3 is intercepted by a recess 40 in the button. To release the bolt from the button 37 the bolt is taken back again by the knob 7 whereupon the button springs out to its inoperative position and the snib 32 takes over control of the bolt once more.

Turning now to Figures 8 and 9 these show more fully the construction and arrangement of the knob 7 and a locking mechanism therefor. The knob comprises a die-cast shank or barrel 41 journalled and axially slidable in the lockcase 1, and upon which is fastened a profiled plastics hand-grip 42. The knob is shown in these Figures in its normal axial position in which it is free to rotate, the rear end of the barrel 41 being connected to the cam 21 (which is in turn retained by the plate 23) whereby turning the knob withdraws the main bolt as described above.

A cylinder plug 43 is borne in the barrel 41 and is either free to rotate in the barrel or is locked thereto depending upon the condition of the key-operated cylinder mechanism of which it forms a part. This mechanism is operated by the same key 5 as the outside cylinder 6 and may be of any convenient type based on eg pin or disc tumblers, but in the preferred embodiment employs apertured plate-like tumblers of the type exemplified by our United Kingdom Patent Specification No.

1030921. Thus, a stack of such tumblers is disposed within the plug 43 as indicated at 44, being nipped between the front end of the plug and a bush 45 pressed against the rear end of the stack by a spring 46. Each tumbler 11 is normally biased to project beyond the periphery of the plug 43 (laterally of the plug as viewed in Figure 9) to engage in one or other of a pair of slots (not shown) formed in the bore of the barrel 41 and thereby prevent rotation of the plug relative to the barrel. The retraction of the tumblers 44 to lie wholly within the plug 43 in order to allow rotation of the latter in the barrel 41 is effected by the initial rotation of the key 5 inserted through the key-entrance 47 and into profiled apertures in the tumblers, as described in Specification No 1030921.The rear end of the plug 43 is formed with an eccentric peg 48 which extends into a drive slot 49 of an abutment member 50 which is thus radially extendable and retractable by corresponding rotation of the plug 43, the abutment member being retained in a groove 51 in the rear of the barrel 41 by a cap 52.

In the usual rotary position of the plug 43 in the barrel 41 (ie that in which the tumblers 44 lock the plug to the barrel) the abutment member 50 is in its extended position and when, as illustrated, the barrel 41 is in its normal (outward) axial position relative to the lockcase 1 the member 50 extends from the barrel and into the part-annular space defined between the plate 23 and a facing shoulder 53 of the lockcase. The member 50 also engages in a radial notch 60 formed in the cam 21 to further establish the rotary connection between the knob and cam. In this condition the abutment member locates the knob in the axial sense relative to the lockcase, but is free to rotate together with the knob and cam to the extent required to achieve withdrawal of the main bolt.

At its front end, the barrel 41 is formed with a pair of projections 54 extending radially outwards from the main body of the barrel, and rearwards towards the lockcase. In this region the lockcase is provided with an annular skirt 55 surrounding the barrel 41 and formed with a pair of recesses 56 complementary to the projections 54, which face the projections 54 when the knob 7 is in its at-rest rotational position (ie not withdrawing the main bolt). In the normal axial position of the barrel 41, however, the projections 54 and recesses 56 remain out of contact and impose no constraint on the rotation of the knob.

In order to lock the knob 7, the key 5 is inserted into the plug 43 and turned to unlock the plug from the barrel 41, further turning of the key through a total of 180 being effective to rotate the plug in the barrel such as to withdraw the abutment member 50 from the notch 60 and into the barrel. With the key in the same position the whole knob 7 can now be pressed in relative to the lockcase, against the bias of an ejector spring 57, and so as to engage the projections 54 in the recesses 56, the rear end of the barrel with the abutment member 50 and cap 52 passing through the central apertures in the cam 21 and plate 23 in this movement.With the knob pressed in fully the key is turned back to its original position and removed, in so doing the plug 43 being rotated back in the barrel 41 to extend the member 50 once more, and the plug being locked again to the barrel. In this condition the member 50 engages behind the plate 23 (as shown in chain line in Figures 5 and 9) to retain the knob with the projections 54 engaged in the recesses 56, thus to prevent rotation of the knob 7.

Unlocking the knob 7 involves the same key operation as described above for locking the knob, except that in this case when the member 50 is withdrawn the knob is allowed to move axially away from the lockcase under the bias of the spring 57 to disengage the projections and recesses 54/56. In all positions of the knob 7, a skirt 58 on the handgrip moulding 42 shields the formations 54/56.

As will be appreciated, the cooperating abutments provided by the projections 54 and recesses 56 are of a more substantial size and adapted to resist greater forcing loads than the knob-locking abutments in typical prior art nightlatches discussed previously. Although only two such projections and recesses are shown in the Figures, a continuous circumferential series of such formations can be provided if desired around the barrel 41 and lockcase skirt 55 to form a complete ring of interlocking ' "castellations".

If desired, the above-described mechanism can also be adapted so as to disengage the rotary connection between the knob 7 and cam 21 when the knob is locked in its inner position. A disengagement function is provided in some prior art locks (such as that described in Specification No 687223) to provide protection against bolt-withdrawal in the event that the knob is successfully forced, but normally should not be necessary in a lock as described herein in view of the high resistance to knob forcing achieved by the formations 54/56. Nevertheless this function could be provided by modifying the shape of the aperture 8 in the cam 21 to eliminate the connection between the knob and cam previously provided through the flats 22. The keying of the knob to the cam for rotation thereof is now left solely to the engagement of the abutment member 50 in the notch 60.

As previously described, when the knob is locked in its inner axial position the member 50 is out of engagement with the notch 60 and so even if the knob could be forced round in this condition the cam would not be rotated to withdraw the bolt. Re-establishment of the connection between the knob 7 and cam 21 could only be achieved through use of the correct key in plug 43 to withdraw the abutment member 50 from behind the plate 23 and re-engage it in the notch 60.

Claims (5)

1. A lock comprising a manually-operable member rotatably mounted with respect to a lockcase for withdrwing a bolt of the lock; the manually-operable member also being capable of limited axial displacement between first and second positions respectively outward and inward with respect to the lockcase; the lockcase and manually-operable member having complementary formations which, when the manually-operable member is in its said second axial position, engage together to block rotation of the manually-operable member but which, when the manually-operable member is in its said first axial position, disengage to permit rotation of the manuallyoperable member for withdrawing said bolt; a key-operated cylinder mechanism incorporated in the manually-operable member and being rotatable and axially displaceable as a whole therewith; the cylinder mechanism comprising a plug normally locked against rotation relative to the manually-operable member but being rotatable relative to the manually-operable member by a correct key, and an abutment member normally extending transversely from the cylinder mechanism but being movable to a withdrawn position by rotation of the plug relative to the manually-operable member; with the manually-operable member in its first axial position and the abutment member in its extended position the abutment member permitting rotation of the manually-operable member but blocking displacement of the manually-operable member to its second axial position; and with the manually-operable member in its second axial position and the abutment member in its extended position the abutment member blocking displacement of the manually-operable member to its first axial position, thereby to maintin said complementary formations in engagement to block rotation of the manually-operable member; displacement of the manually-operable member between its first and second axial positions thus requiring rotation of the cylinder plug relative to the manually-operable member to withdraw the abutment member.

2. A lock according to claim 1 wherein said lockcase comprises an annular skirt portion extending outwardly from the body thereof and encircling a shank portion of the manually-operable member, the outer end of said skirt presenting one or more axially-facing recesses or projections, and a portion of said manually-operable member presenting one or more complementary projections or recesses which face and remain spaced from the recesses or projections of the skirt while the manually-operable member is in its said first axial position and which engage therewith when the manually-operable member is in its said second axial position.

3. A lock according to claim 1 or claim 2 further comprising a locking member within said lockcase biased to a locking posiion in which it blocks withdrawal of said bolt whenever the latter is extended and being operatively associated with said manually-operable member whereby rotation of the latter dis places the locking member from its locking position prior to withdrawal of the bolt; and a snib borne by the lockcase biased to a retaining position in which it blocks extension of said bolt whenever the latter is withdrawn, said snib having a portion which extends out of the lockcase when in its retaining position whereby contact of said portion with a strike member for said bolt displces the snib from its retaining position to permit extension of the bolt.

4. A lock according to claim 1 and substantially as hereinbefore described with reference to Figures 8 and 9 of the accompanying drawings.

5. A lock substantially as hereinbefore described with reference to Figures 1 to 9 of the accompanying drawings.