CYLINDER LOCK

Abstract: A cylinder lock (1) comprises a lock cylinder (2) and a key-operated cylinder plug (3). A latching element (10) is located in the region of the boundary surface between the lock cylinder and the plug and is activated by an electrically actuable blocking element (11) which is movable between a release position and a blocking position. The plug cannot be turned by means of the key when the blocking element is in its blocking position. The latching element (10) has a length which is slightly shorter than the axial length of the plug (3).

Description: Cylinder Lock Technical Field The present invention relates to a cylinder lock of the kind defined in the preamble of Claim 1. In addition to their normal key-operated function, cylinder locks of this kind which also include an electrically-operated blocking function find use in many different areas. One such area is in controlling access to a locality or building in which a person in possession of a key to the lock is authorized access to the locality or building only at certain times of the day. The electric blocking function is able to prevent access automatically at predetermined times. In other cases, the lock key is provided with an elec- trie code in addition to the normal key code. In this case, the key may include a transmitter which trans¬ mits a signal which is captured by an antenna located in the vicinity of the lock. When the signal transmit¬ ted from the key is the correct signal for that parti- cular lock, the electric blocking function of the lock is deactivated, therewith enabling the key to be used in the normal manner. This enables various passage control systems to be constructed without needing to provide authorized and unauthorized persons with a number of different keys at different times. Naturally, attempts are made to force system locks that are equipped with electric blocking functions of the kind meant here, and it is therefore advantageous when the electrically activated blocking devices are able to make forcing of such locks more difficult. Background of the Invention Various types of electrically actuable cylinder plug blocking devices are known to the art. For instance, US-A 3,241,344 (Peters) discloses a key- activated cylinder lock which is intended to secure a deck lid, for instance, and which can also be acti¬ vated electrically. This lock arrangement includes two mutually independent actuable locking devices which coact in a locked state but which can be actuated selectively and alternatively to open the lock. To this end, there is used a blocking element which is activated by an electromagnet or solenoid and which also coacts with a key-activated side-bar. The block- ing element has a pointed end and engages with an obliquely positioned hook in the cylinder plug peri¬ phery, in the region of the side-bar. The cylinder lock can be opened by turning the key, whereupon the side-bar is withdrawn and the pointed end of the blocking element is displaced radially inwards while engaging the hook as the cylinder plug is turned against the action of a spring. The lock can also be opened by energizing the electromagnet, whereupon the blocking element shaft, which forms the electromagnet armature, is drawn into the coil so that the plug can be freely rotated. CH-A-653,400 (Bauer Kaba) discloses a cylinder lock which includes an electromagnetically activated and axially movable side-bar which is mounted in a slot or recess in the end of the cylinder plug located outside the lock housing. When the side-bar is located in an axial position, the plug can be rotated by means of the key, whereas in another axial position the side- bar is accommodated in a recess which prevents the plug from being turned. EP-0 278,906 (Berchtold) discloses an electromagnetic cylinder lock provided with a key which is coded both electronically and mechanically. Electronic elements in the form of a microswitch and an electromagnet with armature are provided. The armature is movable in the direction of its long axis and forms part of a latch¬ ing device which engages in the cylinder plug through the medium of a release pin and a particularly confi¬ gured tumbler pin. Located parallel with the release pin is a latching pin which engages in the plug and also in the armature. In order to open the lock, it is necessary for the mechanical latching pin of the lock and also the microswitch, the release pin, the arma¬ ture and the latching pin to be located in their correct positions. This cylinder lock is comparatively complicated and its latching elements are comprised of radially mov¬ able pins of round cross-section. The electromagnet armature, which can be moved axially, is located at a not inconsiderable distance from the plug and the cylinder has relatively large dimensions, so as to be able to accommodate all components. The actual elec¬ tromagnet armature has a complicated construction and includes several different grooves and recesses. EP-A1-0 453,878 (BKS) describes a lock plunger which includes tumblers and an electromagnetic locking func¬ tion. A radially directed side-bar is spring-biassed outwardly to a release position. The head of the elec¬ tromagnet armature lies against the side-bar and the armature is also urged radially outwards by means of a spring. When the electromagnet is energized, the arma¬ ture is moved towards the cylinder plug and holds the side-bar in its latching position. Thus, in this case, the lock includes a radially extending latching element, i.e. a latching element without axial extension which is activated by a radi¬ ally directed electromagnet - for instance similar to the latching element in the arrangement disclosed in US-A 3,241,344. The patent specification also discloses how to prevent the electromagnet from being rendered non-functional electrically by unauthorized persons attempting to open the lock. Similar lock structures are described in EP-A2-0 281 507 (Zeiss Ikon) and EP-A1-0 303 849 (BKS) . In all of the aforedescribed lock plugs or cylinders, the plug is blocked electromagnetically by radially directed elements, primarily different types of pins which prevent the plug from being turned. Locks of this kind are normally relatively easy to force. Another method of forcing such a lock is to use violence, such as to subject the pins to shear forces at the interface between plug and lock cylinder. The latching pins or like devices will fracture even when only a relatively moderate force is used on the lock, therewith enabling the lock to be opened. Object of the Invention One object of the present invention is to eliminate the aforesaid drawbacks and other drawbacks of known locks of the kind meant here, i.e. locks which include two or more mutually independent latching or blocking devices, of which at least one can be activated elec¬ trically. Another object is to provide a lock of the aforesaid kind in which the occurrence of shear forces in the electrically actuable latching elements of the lock are avoided to the greatest possible extent should the lock be subjected to violence or to vigorous vibra¬ tions in an attempt to open the lock. A further object is to provide a lock of the kind meant here which has two or more mutually independent lock functions and which can be manufactured simply and is reliable in use. Summary of the Invention These and other objects are fulfilled with an inven- tive cylinder lock of the aforedefined kind which has essentially the characteristic features set forth in the characterizing clause of Claim 1. Because the latching element has a certain axial length in relation to its thickness or diameter and is located in the region of the boundary surface or interface between the lock cylinder and the lock plug and coacts with a blocking element, the latching element can only be moved radially outwards from the cylinder plug when the blocking element is located in its release position, therewith rendering forcing of the lock difficult. If an attempt is made to force the lock, the latching element is held blocked, i.e. it is not free to move radially, therewith making forcing of the lock extremely difficult to achieve. Further, shear forces are avoided when violence is used against a cylinder lock that is provided with a latching element of this kind, since the latching element will be subjected to pressure forces which tend to clamp the latching element in engagement with the blocking element. Both the latching element and the blocking element may have a simple form, which are suitably adapted to one another, for instance so that projections on one of the elements are corresponded by recesses on the other elemen . Preferably the blocking element is movable in its axial direction and will present a part having axial length which extends at a short distance from the latching element. This enables the latching element and the blocking element to be readily adapted to one another, so that reliable blocking of the latching element can be en¬ sured. For example, according to one preferred embodiment, the mutually engaging parts of the latching element and the blocking element may include respective pro¬ jections and recesses which coact mutually in the lock release position, wherein as the blocking element is displaced axially to its blocking position, the pro¬ jections will engage with a plain part of the second element that lacks a recess and therewith block move¬ ment of the latching element to its release position. The blocking element is conveniently moved axially by means of an electric motor, an electromagnet, a sole¬ noid or some like device, preferably including a shaft which extends parallel with the axis of the latching element and the cylinder core. One solution which has been found effective in prac¬ tice is characterized in that axial movement of the blocking element is achieved by means of an electric motor whose output shaft coacts with an element which is connected to the blocking element and which con¬ verts rotary motion of the motor to rectilinear mo¬ tion. With an arrangement of this nature, the rotary motion of an electric motor can be converted to precise rectilinear motion for displacement of a blocking element, wherein the end positions of the blocking element which determine the blocking and release position extremities of the latching element are accurately defined. At the same time, the electrical component of the blocking arrangement can be given a simple and inexpensive design and will be highly reliable in operation. Furthermore, an arrangement of this nature also has the important advantage of being insensitive to heavy vibrations. As before mentioned, the configuration of the latching element may vary. For instance, in the case of one embodiment, the latching element is comprised of a round rod having an axial extension which is slightly shorter than the length of the cylinder plug. Recesses are formed in the rod at appropriate positions there¬ on, these recesses corresponding to projections on the blocking element. The latching element may preferably be pressed towards its latching position by means of springs which engage in the region of the ends of said element. The invention will now be described in more detail with reference to a number of exemplifying embodiments thereof and also with reference to the accompanying drawings. Brief Description of the Drawings Figure 1 is an exploded view of a cylinder lock in which the plug can be prevented from rotating by means of a latching element which is activated by an elec¬ trically operating blocking device. Figure 2 illustrates the cylinder lock of Figure 1 in an assembled state and also shows a key belonging to the lock. Figure 3 is a sectional view of the cylinder lock of Figures 1 and 2, taken on the line III-III in Figure 4. Figure 4 is a sectional view of the cylinder lock of Figures 1-3, with the plug latching element shown in a blocked position. Figure 5 is a view corresponding to the view of Figure 4, showing the latching element in its release posi¬ tion. Figure 6 is a front view of a modified embodiment of the cylinder lock of Figures 1-5. Figure 7 is a partially cut-away side view of an inventive cylinder lock provided with another type of blocking device. Description of Preferred Embodiments With reference to Figures 1-5, the reference numeral 1 identifies a cylinder lock having a lock cylinder 2 which accommodates a plug 3. The plug 3 can be rotated in a conventional manner, by means of a key 4 inserted into the key slot 3a of the plug 3. The key 4 is provided with a top code 4a and a side code 4b which activate a row of side tumblers 5 which, in turn, activate a side-bar 7, as will be seen from Figure 3. When the correct key is used to turn the plug 3, the side-bar 7 is able to move radially in¬ wards in the plug, so as to enable the plug to be rotated. The cylinder lock is also equipped with an electric blocking function, the active part of which is prima¬ rily a latching element 10 which engages in a V-shaped groove 3c in the peripheral surface of the plug 3. The latching element 10 has an axial length which is slightly shorter than the axial length of the plug and is located in the region of the boundary surface between the lock cylinder and the plug. When in its active position, the latching element 10 will there¬ fore lock the plug against rotation by the key 4. This plug blocking function is achieved with the aid of a blocking element 11 which functions to block the latching element 10 and which can be moved axially between a release position, shown in Figure 5, and a blocking position, shown in Figure 4. The latching element 10 has a round cross-section and is comprised of a cylindrical element having two circumferentially extending grooves 10a and spherical end-parts 10b. Springs 15 act against the end-parts 10b and urge the latching element 10 inwardly towards the plug. The blocking element 11 has two projections 11a which engage with the periphery of the latching element when the blocking element is in its active blocking posi¬ tion. In the release position, i.e. when the blocking element 11 has been moved axially from the blocking position shown in Figure 4 to the release position shown in Figure 5, the projections 11a are in line with the grooves 10a on the plug 10, therewith en¬ abling the latching element to be pressed radially outwards as the plug 3 is turned with the key 4. In the embodiment illustrated in Figures 1-5, this axial movement of the blocking element 11 is effected with the aid of an electric motor 12, the bearing shaft 13 of which has a screw-threaded part 13a which coacts with a corresponding screw thread on a nut part lla connected to the blocking element 11. When the motor is energized, the motor shaft 13 is caused to rotate through a given number of revolutions, such that the blocking element 11 will move axially between its two end positions corresponding to the blocking position of the blocking element and its release posi¬ tion, respectively. Figure 7 illustrates a modified embodiment in which the electric motor 12 is replaced with an electro- magnet whose coil 17 is connected to the blocking element 11. The armature 18 of the electromagnet lies against a stationary part of the unit which includes the electric drive means. When the electromagnet 17, 18 is energized, the coil 17 is caused to move to the right in Figure 7, therewith moving the blocking element 11 from its active latching-element blocking position shown in Figure 7 to its latching-element release position. It will be understood that other types of electric drive means may alternatively be used. Figure 1 illustrates how the components of the elec¬ tric drive means are carried by and mounted in the lock cylinder 2. The main part of the mounting device is comprised of a T-shaped element 20 having a plate 20a which is screwed firmly to the lock cylinder 2 by means of two screws 21. The mounting element 20 has two legs 20b, 20c which extend outwardly from the plate 20a and which carry the electric motor 12 and the blocking element therebetween. It will be seen from Figure 6 that the mounting ele¬ ment 20 and the parts associated therewith may alter¬ natively be attached to the lock cylinder in another way. In the Figure 6 embodiment, the plug 3 includes a row of tumblers which coact with the system code 4a of the key 4, without being obstructed by the electrical blocking means. Various devices can be used to activate the electric blocking function. For instance, the blocking means may be controlled by a timer which at predetermined time points will send a start impulse to the motor 12 so as to cause the blocking element 11 to be moved to its blocking position. The lock cannot be opened with the key with the blocking element in its blocking position. Alternatively, the key may be provided with a trans¬ mitter 4c which transmits code signals that are cap- tured by an antenna on the lock cylinder, as indicated in Figure 2. The antenna may be located within the region indicated in chain lines in Figure 2 and is connected to an intelligent unit which detects the authenticity of the code signal transmitted by the key, and which when the code signal is found to be correct sends a start impulse to the motor 12 for movement of the blocking element 11 to its release position. The lock can then be opened after inserting and turning the key 4. A blocking means constructed in accordance with the invention will fit all types of lock cylinders, such as -round cylinders, oval cylinders and profiled cylin¬ ders, without requiring undue modification. The configuration of the latching element 10 can vary within wide limits. An essential feature, however, is that the latching element will conform to the shape of the groove or recess in the cylinder plug. Its length may vary but preferably it exceeds half the axial length of the plug and may - as in the illustrated embodiments - often substantially correspond to the axial length of the plug. The latching element, which shall be located in the region of the boundary surface between plug and lock cylinder, may, alternatively, comprise a plurality of separate elements which together function as indicated above. For instance, it is conceivable for the latch¬ ing element to comprise a plurality of mutually adja- cent balls or some similar elements of limited axial extension which together function as an element having a certain axial length and which coact with one or more suitably shaped blocking element(s) which is/are movable between release and blocking positions.

Claims: Claims 1. A cylinder lock comprising a cylinder plug (3) which is mounted for rotation in a lock cylinder (2) and which includes one or more lock elements, such as a row of pins or tumblers or a side-bar (7) which are activated directly or indirectly by means of a key (4) , and further comprising a latching element (10) which is mounted in the lock cylinder (2) and which in an active position prevents turning of the plug (3) and in a release position permits the plug to be turned, said latching element being urged by spring means (10) towards its latching position and coacts with an electrically activated blocking element (11) mounted in the lock cylinder, wherein in one position the blocking element (11) permits the latching element (10) to move radially to its release position, and in another position blocks the latching element in its locking position, c h a r a c t e r i z e d in that the axial length of the latching element (10) is substantially greater than its thickness or diameter, that it is located in the region of the boundary surface between the lock cylinder (2) and the cylinder plug (3) , that it engag¬ es in an axially extending groove (3c) or recess in the plug and that it can move radially outwards to its release position, when the blocking element (11) is in its release position and the plug is turned by the key or in some other way. 2. A cylinder lock according to Claim 1, c h a r a c t e r i z e d in that the blocking ele¬ ment (11) is movable in its axial direction and has a part with axial extension at a small distance from the latching element (10) . 3. A cylinder lock according to Claim 1 or 2, c h a r a c t e r i z e d in that the mutually adja¬ cent parts of the latching element (10) and the block¬ ing element (11) include projections (11a) and recess- es (10c) which coact mutually in the release position and which projections engage a part of the other element that lacks a recess as the blocking element (11) is moved axially to the blocking position, there¬ with blocking movement of the latching element (10) to its release position. 4. A cylinder lock according to Claim 3, c h a r ¬ a c t e r i z e d in that axial movement of the blocking element (11) is achieved by means of an elec- trie motor (12) , an electromagnet (17) or the like, preferably having a shaft (13; 18) which is parallel with the axis of the latching element and the cylinder plug. 5. A cylinder lock according to Claim 4, c h a r ¬ a c t e r i z e d in that the axial movement of the blocking element is achieved with the aid of an elec¬ tric motor (12) whose output shaft (13) coacts with an element which is connected to the blocking element (11) and which functions to convert the rotary motion of the motor to rectilinear motion. 6. A cylinder lock according to Claim 5, c h a r ¬ a c t e r i z e d in that said element which coacts with the bearing shaft and the blocking element, respectively is comprised of a screw/nut arrangement, a worm gear or like device. 7. A cylinder lock according to Claim 5, c h a r - a c t e r i z e d in that the electric motor output shaft (13, 13a) has a screw thread which coacts with a corresponding screw thread on a nut part (11a) which extends at right angles to a part (11) functioning as a blocking element and is connected to said part, wherein when energized the electric motor rotates through a predetermined angle of rotation or a pre¬ determined number of revolutions in one or the other direction while moving the blocking element (11) between its end positions. 8. A cylinder lock according to Claim 4, c h a r ¬ a c t e r i z e d in that the blocking element is connected to a movable part of the electromagnet. 9. A cylinder lock according to Claim 1, c h a r - a c t e r i z e d in that the spring means includes two springs (15) one engaging the latching element (10) at each one of its ends.

Inventors: THORDMARK MAGNUS, WALLDEN LARS, THORDMARK, MAGNUS, WALLDEN, LARS
Applicants: ASSA AB
Application year: 1993
Main classification: E05B47
IPC codes: E05B47, G07C9