KEY OPERATED MECHANISMS FOR LOCKS

Abstract: A key operated mechanism includes a lock-case (1) and a rotatably mounted plug (8) located wholly within the lock case and having an axial key hole. Angularly spaced passageways (16) extend through the plug from the key hole to the outer surface of the plug and each passageway receives a detaining member (21) adapted to slide therein. A pair of locking rings (4) fixed with respect to the case have angularly spaced openings which are in register with the passageways in the plug when the plug is in a correct rotational position to enable the detainers to be moved outwardly. When each detainer is moved outwardly by a respective present amount the plug may be rotated. The key for the mechanism has two groups of angularly-disposed indents (34, 35) spaced axially along its shank. The indents are of a depth to appropriately move the detainers. One group of indents operates the detainers when the key is entered from one side and the other group when the key is entered from the other side.

Description: "KEY OPERATED MECHANISMS FOR LOCKS" DESCRIPTION This invention relates to key-operated mechanisms for locks. In some types of known key-mechanisms detainers are mounted in tier order within the depth of the lock-case. The number of different combinations of detainers is restricted by the need for the detainers to he mounted in symmetrical order and the inconvenient and expensive deep case needed to accommodate additional detainers. In other types of locks the key-mechanism is contained within a " barrel or cylinder, and the detainers may take the form of pin-tum lers, wafers, sliders or pivoted and pivotless levers. However, two such key- mechanisms are necessary to enahle key-operation from " both sides of the lock. The lock is correspondingly more expensive and may only he used on relatively thick doors. Key mechanisms of the cylinder type are fitted to the door separately to the lock to-which they are operatively connected and the need to cut away a substantial part of the thickness of the door to accommodate the cylinder weakens the door. The keyhole of such mechanisms on the outside of the door is vulnerable to attack and vandalism. The present invention seeks to provide a key-operated mechanism capable of being mounted within a lock-case of relatively small thickness to reduce restrictions on where it may be used. The mechanism is capable of being operated from each side of the lock and may provide a large number of different combinations of detainers in relation to the quantity of detainers incorporated in the mechanism. According to the present invention there is provided a key-operated mechanism for a lock comprising a lock-case, a rotatably mounted plug member located within the lock-ease and having an axial keyhole and a plurality of angularly-spaced transverse passageways communicating with the keyhole and extending to the outer surface of the plug member, each passageway receiving a detaining member or assembly adapted to slide along the passageway and being biased towards the axial keyhole, ■ - ϊ-iz one or more locking members fixed in . relation to, or being part of, the lock case having angularly spaced openings which are in register with the transverse passageways in the plug member when the plug member is in a predetermined angular position to enable the detaining members to be moved outwardly from the plug member, each detaining member or assembly linking the plug member and a locking member and allowing relative rotation between the plug and locking members only when the detaining member or assembly is at predetermined position along its passageway, and a key having two groups of angularly-disposed indents, axially spaced along the key, each group having indents corresponding to each of the detainers in the mechanism and of such a depth as to cause the detainers to be moved to their predetermined positions along their respective passageways, wherein one of the groups of indents is arranged to correspond to the detainers when the key is entered from one side of the mechanism and the other group of indents is arranged to correspond to the detainers when the key is entered from the other sid The locking member may include a series of arcuate flanges disposed in a ring and extending generally parallel to the keyhole the spaces between the flanges providing said angularly spaced openings, and a series of said detainers being located in a circular configuration, each having a slot for receiving said flanges, the slots in the series of detainers being located in the ring of the arcuate flanges when the detaining members are moved each to it respective predetermined position, thereby allowing the plug member and detaining members to be rotated with respect to the locking member. The detaining members are arranged in two axially spaced circularly-configured series, the mechanism including two locking-rings with said arcuate flanges each locking ring co-operating with a respectiv series of said detaining members. The present invention also provides a key as defined above and adapted to form part of the key- operated mechanism as aforesaid. Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings. In the drawings:- Figure i is an axial sectional view of a key-mechanism in accordance with the present invention, showing the mechanism in a locked position. Figure 2 is an elevation view of a locking- ring which is part of the mechanism of figure 1; Figure 3 s a radial sectional view of a plug which is part of the mechanism of figure 1; Figure is an elevation view of a single detainer which is part of the mechanism of figure 1; Figure 5 is a transverse sectional view of the key mechanism of figure 1; Figure 6 is an elevational view of a key blank for use with the mechanism; Figure 7 is an axial sectional view of the mechanism with the key entered from one side and in an unlocked position; Figure S is an axial sectional view- corresponding to Figure 7 but showing the key entered from the other side; Figure 9 is a radial sectional view of an alternative form of plug and detainer; and Figure 10 is an axial sectional view of an alternative construction of the locking rings. A key-operated mechanism comprises a lock- case 1 and a cover plate 2 each having respective key holes, in register. The lock-case is of conventional mortice-lock size. Both the key holes in the lock case 1 and cover plate 2 are circular in cross-section, but, in addition, that of the cover plate 2 is restricted by a segmental projection 3 acting as a key abutment, described in more detail below. A locking ring (shown separately in Figure 2) comprises a circular plate portion 5 with a central .circular hole. The locking-ring has a ring of arcuate flanges 6 projecting perpendicularly from the radially outer margi of the plate portion 5. The arcuate flanges are separated by slots 7 > these being disposed at predetermi positions around the locking-ring. One locking-ring is non-rotatably mounted to the inside face of the lock case and another non-rotatably mounted to the inside face of the cover plate 2 such that their circular holes are in register with the key holes in the lock-case 1 and cover plate 2, and so that the arcuate flanges 5 project inwardly. A plug 8 (shown separately in Figure 3) is generally cylindrical in outline and formed with a 8 central circular key-way. A pair of segmental projections 9 are located at one end of the plug key- way to define a slot 10 between them. The radially outer portion of the plug has two circumferential channels 11 and 12. The channels 11 and 12 are symmetrically spaced to leave an annular circumferential flange 13 between them and two outer circumferential flanges 14 and 15. Two sets of radial slots 16 are axially spaced along the plug, and within each set the radial slots 16 are spaced at angular intervals arou the plug. Each slot 16 communicates with one of the channels 11, 12 at one end and with the plug key-way at t other. The disposition of the slots 16 in each set corresponds with the disposition of the slots 7 in respective ones of the locking rings. Longitudinal bores 17 are located through the annular flanges 13-15 at 120 intervals. The forward and rear faces of the plug 8 each have a circular recess 18 with a circular channel 19 at the margin of each recess 18 communicating with a slot 16, the recess and channel being configured to receive respectively the body and arcuate flanges 6 of a locking ring k . . The plug 8 includes a cam 20 projecting from the outer surface of the outer circumferential flange Ih. and replaceably fixed to the body of the plug. The cam 2 provides the operating connection between the key mechanism and other associated parts of a lock or bolt mechanism. The plug 8 is rotatably mounted in the lock case i between the locking rings 4, the arcuate flanges 6 of the locking rings being received in the channels 19 in the end faces of the plug. A respective detainer 21 (shown separately, by way of example, in Figure 4) is located for sliding movement in each radial slot 16 of the plug. Each detainer 21 is generally flat and at one end is tapered. At its other, outer, end the detainer has a rectangular lateral protrusion 22, the surface 23 of which, being perpendicular to the main portion of the detainer, acts as an abutment surface, as is described below. Spaced from the lateral protrusion 22, towards its tapered end the detainer has a rectilinear slot 26. The distance between the slot 24 and the tapered end is a predetermined characteristic of each detainer. At its outer end .the detainer has a bent portion 25 extending transversely to the plane to the main surface of the detainer. Each detainer is located in one of the radial slots 16 in the plug 8, and extends through a slot 7 in one of the locking rings 4, the formed end of the detai projecting outside the slot 16 in the plug to rest on the circumferential surface of one of the circumferential channels in the plug to prevent removal of the detainer through the keyhole and to limit the projection of the detainer into the keyhole. The detainers 21 are urged towards the keyhole by spiral springs 26. The spiral of each spring is fixed to the plugs 8 by a pin 27 fixed in one of the bores 17 in the plug. One arm of each spring presses down on the bent end portion 25 of a detainer and, where convenient, the other arm of the spring bears on another one of the detainers. Each detainer is urged into the keyhole until it abuts with the surface of the plug as aforesaid and in this position the slots 25 of the detainers are misaligned with the ring of arcuate flanges 5 on the locking ring. Thi position is shown in Figures 1 and 5 , and it will be appreciated that the plug 7 is thus prevented from rotating within the case. Referring to Figures β and 7 a key for the mechanism comprises a shank 23 of appropriate form to the keyhole. The shank is generally cylindrical, the forward portion being trunicated longitudinally to leave a flat surface 29. The rear portion of the stem in line with the flat surface 51 of the rib 30 constitutes an abutment shoulder. The bow 5 of the key is made as part of, or fitted to, the shank at one end. The other end of the shank is tapered to enable the key, when entered into the keyhole, of the mechanism to impart initial movement, or lift, to each detainer 21. At the end of the forward portion of the shank, where it meets the rear portion it is provided with a circumferential groove 33. Figures 7 and 8 show the fully formed key including two equivalent sets 34 and 35 of indents, one on either side of the groove 35. In the present embodim of the invention the locking mechanism includes two sets of angularly spaced detainers. Thus each set of indents comprises one angularly spaced series of indents 34a, 35 Each indent is counter-sunk to ensure the easy lift of the detainers as the key is entered or withdrawn and provided with a flat base to co-operate with the tapered end of the detainers. The key may be entered into the mechanism from either side. Figure 7 shows the key entered from the cover plate side. To enter the key it must be disposed such that its flat surface 29 is flush with the upper surface of the segmental projection 3 in the cover plate. The key is inserted until the abutment shoulder of the rear portion of the shank of the key abuts the outer face of the cover plate. The circumferential groo 33 in the shank enables the key to be rotated with the wall of the cover plate being accommodated in the groove. The key will rotate in this position only and thus correspondence between the forward series of indents 34 and the detainers 21 is assured. Figure 8 shows the key entered from the lock-case side of the mechanism. The shoulder 31 of the rear portion of the shank of the key abuts the inside face of the segmental projection 3 on the cover plate and further insertion is prevented. The groove 33 in the shank again accommodates the wall of the cover plate to allow the key to rotate. When entered in this way the two series of indents 35 nearer the bow of the key are located in register with the two sets of detainers 21. The indents in each set 34 and 35 are symmetrically identical as are the indents in each set 34 and 35. Each set comprises two series of angularly spaced indents each conforming with a respective one of the sets of detainer positions. The indents are of a predetermined depth to provide the necessary lift to each detainer to align the slot 24 in each detainer with the ring of arcuate flanges 6 in the locking ring. When the key is entered from the O FI cover plate side (Figure 7) the flat surface 29 of the key lies flush against the flat surface of the segmental projections 9 in the keyway of the plug 8. Thus rotation of the key in the casing causes the plug 8 also to rotate. When the key is entered from the lock-case side of the mechanism (Figure 8) the forward portion of the key projects beyond the lock mechanism and the longitudinal rib 30 in the rear portion of the shank fits in the slot 10 between the projections in the plug. Thus the plug is constrained to rotate with the key. Rotation of the plug results in the rotation of its cam portion 20 which in turn contacts associated parts for operation of the locking mechanism. It will be appreciated that during rotation of the key in the mechanism one of the sets of indents 34 or 35 is outside the mechanism and rotates without hindrance. Such an arrangement does not necessitate any alteration in shape, or enlargement, of the keyhole. In an alternative version the indents are formed by terminating a tapered slot, extending from the tapered end of the key, at a position and depth to provide the predetermined lift to the respective detainers. To deter unauthorised operation of the mechanism, bv for example, picking (which comprises the f OM use of an instrument, other than a key, in the keyhole to lift the detainers to the position for rotation of the plug) one or more detainers may be provided with a shallow rectangular recess across its side surface for engagement with the lockin -ring. The shallow recess is so positioned on the detainer to align the shallow slot to the locking ring when the detainer is in a non-fully lifted position. The application of torque to the plug will serve only to cause engagement between the locking ring and the shallow recess. As a further security precaution one detainer may be arranged to require no lift to align its slot with the locking ring. The indent in the key corresponding to this detainer will therefore need to be of greater depth than usual and will not then lift the detainer at all. An attempt to pick the lock by raising all the detainers will cause this detainer at least to be misaligned. . The detainers nay be of square or rectangular section with a part of the length reduced in size or formed in diameter to provide a spherical radius at one end for contact with the key. A shoulder is included on the detainer to prevent removal of the detainers through the keyhole and to determine the amount of projection of the end of each detainer into the keyhole in the plug. Alternatively the detainers may be curved or bent along their lengths to increase resistance to picking. Figure 9 shows such a detainer 21a_ in combination with an arcuate slot l6A which further hinders operation with any instrument other than the correct key. As a further alternative the detainers may be of circular cross-section with a groove instead of a slot for engagement with the locking ring when lifted to the operating position. Locking rings are then suitably formed for abutment with the cylindrical detainers. These detaine and corresponding slots in the plug are reduced in diameter along part of their length to prevent the removal of the detainers through the keyhole and to determine the amount o projection of each detainer into the keyhole. Each detaine may have a spherical radius at one end for co-operating wit the indents in the key. In an alternative embodiment of the invention the locking rings are constructed in a tubular form so that they are toroidal in shape with radial slots to receiv the slidable detainers. The locking rings have projecting spigots projecting laterally to their planes and engaged in corresponding sockets in the lock case or cover plate. The locking rings may be etachably mounted within the lock-case by for example extensions from -^JΪi the locking rings engaged in holes in the lock case and cover respectively. The extensions and holes are constructed to prevent rotation of the locking-rings. The ring of arcuate flanges on one locking ring will be engaged in the circular recess in the plug thereby preventing detachment of the extensions on the other locking ring from the corresponding holes in the lock- case/cover. In such arrangement the segmental projection into the keyhole, described above on the cover plate, may be provided on the locking rings. Referring to Figure 9 > in a further arrangemen the two locking rings are each formed as projections from respective halves 40 and 41 of a hollow cylinder. The pro ections 42 are similar to the ring of arcuate flanges in the above-described embodiment of the invention. The cylinder rotatably accommodates the plug and its cam, the latter having an extension passing through an opening in the wall of the cylinder to operate the bolt mechanism of the lock. The two halves are joined together after location of the plug. The unit so constructed may be housed and secured by screws, dowels, welding or adhesive in the lock casing to prevent independent movement or the unit may be used to operate an associated switch. The two halves of the cylinder have cylindrical bushes 43 extending from each end surface to define the entrance and exists to the keyhole. The segmental projection in the keyhole may be constructed as part of the walls of the cylinder or as a projection from the internal surface of one of the bushes 43. It is intended that the engagement of the inward projection of the keyhole in the groove of the key shall prevent removal of the key from the mechanism in any position other than when the channel in the key is aligned to the inward projection of the keyhole. In another form of keyhole the inward projection is formed in the keyhole in the lock-case/cover plate while the keyhole in the plug has the form of the basically circular hole with a segmental projection. It is intended to create various forms of keys and keyholes as a means of providing different combinations by repeating the combinations of detainer lifts in key-mechanisms having non-interchangea forms of keyholes and keys. In a further embodiment of the invention the key-mechanism is of the pin-tumbler type operated by a key of the type described above for use in the sliding detainer-type mechanism. In this further embodiment the locking-ring is cylindrical and has a central bore in which a plug is mounted or rotation. The locking- ring has-radial bores angularly spaced and extending from the central bore to the outer surface of the locking-ring. The locking-ring is non-rotatably mounted within the lock-case. The plug is also cylindrical with a keyhole passing axially through it, the keyhole being formed to engage a key when entered from either end so that rotation of an appropriate key will effect rotation of the plug. The plug also has radial bores extending from the keyhole to its outer surface, these bores being positioned for alignment with thecorresponding bores in the locking-ring when said plug is located in the axial bore in the locking-ring. The radial bores in the plug may have a reduced diameter along part of their length to define a shoulder abutment at a predetermined distance from the position of break¬ through into the key-hole. A spring and upper-pin or driver . is assembled in each radial bore in the locking ring and .a pin is located in each of the shouldered radial bores in the plug. The pins are narrower and wider portions of each pin rests normally on the shoulder in the radial bore to determine the protrusion of the pin into the keyhole and to prevent removal of the pin through the keyhole. To retain the assembly of springs and pins in the locking ring and plug a ring may be fitted around the locking ring, alternatively each individual radial bore may be sealed by for example a small pin, or by indenting the locking ring around each of the radial bores. The spring in each radial bore in the locking-ring exerts a force -on one end of each driver in the locking-ring, the drivers transmitting the force to the end of each respective pin in the plug and causin the other end of said pins in the plug to protrude into the keyhole. In this locked position the driver is located across the surface of intersection between the plug and the locking-ring and thereby prevents rotation of the plug. The length of each driver and the length of each shouldered pin is variable but predetermined and corresponds to the depth of respective indents in the key. The difference between each set of pins in the mechanism and each corresponding depth of indent in the key thereby representing a differ. On the insertion of the appropriate key into the keyhole each shouldered pin is moved to a position according to the depth of the relative indent in the key. The shouldered pins in the plug correspondingly moving each driver against the pressure of its associated spring in the locking- ring so that the position of the interface between each pin in the plug and each corresponding driver in the locking ring is located on the surface of intersection between the locking ring in the plug. The plug may then be rotated by rotating the inserted key. When the key has been returned to the position in which it was inserted in the plug said key may be withdrawn so that under the pressure of the associated spring each driver and pin is urged inwards towards the key-hole in the plug. Instead of using a shouldered pin in a stepped hole in the plug the pins in the plug may be prevented from removal from the plug by the shape of the keyhole. In an alternative design the key may comprise a shank with radial splines to align with the position the detainers in the mechanism, the alignment being achieved when the key is inserted from either side of the lock. The correct position of the key in the lock may be determined by the abutment of one or more of the splines, which are of greater length or of increased thickness than the others, against the lock-case, cover plate, plug or locking-ring. This abutment ensures that one set of indents will co-operate with the appropriate detainers in the mechanism when the key is entered from one side of the lock while a further set of indents in the splines of the key will rotate in the keyhole in the door without the need for enlargement or alteration to the form of said keyhole. When the key is entered in the keyhole from the other side of the door the set of indents in the splines of the key which previousl rotated in the keyhole in the door will co-operate with the respective detainers in the key mechanism while the indents in the key previously in co-operation with the detainers in the mechanism will rotate in the keyhole in the thickness of door again without the need for enlargement or alteration in the form of said keyhole. In many of the types of mechanisms in accordance with the present invention the detainers or corresponding members in the key mechanism may form a single set or several sets. Alternatively the detainers may be positioned at various radial positions in relation to the central keyhole and at various positions in relation,to the end of the key mechanism. \ j s E

Claims: CLAIMS 1. A key-operated mechanism for a lock comprising a lock-case, a rotatably mounted plug member located within the lock case and having an axial keyhole and a plurality of angularly-spaced transverse passageways communicating with the keyhole and extending to the outer surface of the plug member, each passageway receiving a detaining member or assembly adapted to slide along the passageway and being biased towards the axial keyhole, one or more locking members fixed in relation to, or being part of, the lock case, having angularly spaced openings which are in register with the transverse passageways in the plug member when the plug member is in a predetermined angular position to enable the detaining members to be moved outwardly from the plug member, each detaining member or assembl linking the plug member and a locking member and allow relative rotation between the plug and locking member only when the detaining member or assembly is at a predetermined position along its passageway, and a key 23 having two groups of angularly-disposed indents, axially spaced along the key, each group having indent corresponding to each of the detaining members in the mechanism and of such a depth as to cause the detaining members to be moved to their predetermined positions along their predetermined positions along their respective passageways, wherein one of the groups of indents is arranged to correspond to the detaining members when the key is entered from one side of the mechanism and the other group of indents is arranged to correspond to the detaining members when the key is entered from the other side. 2. A key-operated mechanism as claimed in claim 1 wherein a said locking member includes a series of arcuate flanges disposed in a ring and extending generally parallel to the keyhole, the spaces between the flanges providing said angularly spaced openings, and a series of said detainers being located in a circular configuration, each having a slot for receiving said flanges, the slots in the series of detainers being located in the ring of the arcuate flanges when the detaining members are moved each to its respective predetermined position, thereby allowing the plug member and detaining members to be rotated '- SJ A with respect to the locking member. 3. A key-operated mechanism as claimed in claim 2 wherein the detaining members are arranged in two axially spaced circularly-configured series, the mechanism including two locking rings with said arcuate flanges each"locking ring co-operating with a respective series of said detaining members. 4. A key-operated mechanism as claimed in any one of the preceding claims wherein the keyhole of the mechanism, incorporating said keyhole of the plug member, is partially obstructed by a projection from the wall of the keyhole, and wherein the key has an abutment shoulder adapted to abut the projectio from the wall of the keyhole and limit the insertion of the key, the projection and shoulder being located such that when the key is entered from either side of the mechanism the shoulder abuts a respective side of said projection to locate the appropriate group of indents on the key with the detaining members in the mechanism. 5. A key-operated mechanism as claimed in claim 4.wherein the key includes a circumferential channel forwardly adjacent said abutment shoulder and of width to accommodate said projection from the wall of the keyhole to allow the key to rotate. 6. A key-operated mechanism as claimed in any one of the preceding claims, wherein at least part of the wall of the keyhole of the plug member and the cross-section of the key along at least part of its length are so shaped that the key may be entered and withdrawn when in one angular disposition only, the shape of the keyhole and key engaging to such that the plug member is caused to rotate by rotation of the key. 7. A key as defined and adapted to form part of the mechanism as claimed in any one of claims 1 to 6. r>*τ

Inventors: TAYLOR ANDREW MARTIN, TAYLOR JACK WILLIAM
Applicants: TAYLOR ANDREW MARTIN, TAYLOR JACK WILLIAM, TAYLOR LOCK CO LTD
Application year: 1982
Main classification: E05B29
IPC codes: E05B29