WO2010098721A1

WO2010098721A1 - Locking device

Info

Publication number: WO2010098721A1
Application number: PCT/SE2010/050225
Authority: WO
Inventors: Jorma Hirvi; Mathias FÄLT
Original assignee: Assa Ab
Priority date: 2009-02-27
Filing date: 2010-02-26
Publication date: 2010-09-02
Also published as: DK2401456T3; EP2401456A4; PL2401456T3; EP2401456A1; SE533488C2; EP2401456B1; SE0900265A1

Abstract

Locking device comprising a lock mechanism, a forend (1, 101, 201, 301, 401) having at least one bolt opening (9, 109, 209, 309, 409) and at least one bolt (10, 110, 210, 310, 410). The bolt is mechanically- coupled to the lock mechanism and is movable between a position retracted in the direction of the lock mechanism and a position extended through the bolt opening, and has a blocking protrusion (14, 15, 114, 115, 214, 215, 314, 315, 414, 415) disposed inside the forend and projecting in the lateral direction relative to the motional direction, and a front bolt portion (11, 111, 211, 311, 411) disposed in front of the blocking protrusion and, in the extended position, accommodated in the bolt opening with a clearance to the forend. The locking device comprises a covering element which is fixed in relation to the forend and extends parallel with the motional direction of the bolt, which covering element has a first recess which, when the bolt is in the extended position, is disposed laterally outside the blocking protrusion and is open in the direction of the bolt.

Description

Locking device with a blockingfunction to prevent manipulation

Field of the invention The invention relates to a locking device comprising a lock mechanism, a lock pillar and a bolt which is mechanically coupled to the lock mechanism and is movable between a position retracted in the lock housing and a position extended through a bolt opening made in the lock pillar. The invention is especially advantageous in locking devices which are intended for recessed or flush fitting on a door, hatch, gate or the like.

Background of the invention

Locking devices of this kind are usually found, for example, in mechanical locks in external doors to homes. Typically, the lock is of the mortise type. The lock mechanism can be coupled to a lock cylinder and a handle on the outer side of the door for operation of one or more bolts which are each movable between a position retracted in the lock housing and a position extended through the lock pillar, in which extended position they engage with a striking plate in the door frame. Depending on the type of lock and field of application, the bolts can be of various types. Examples of bolts which can form part of a lock having such a locking device are spring bolts, linearly displaceable bolts, swing bolts, hook bolts, and roller bolts. Common to these bolts is that, in their extended position, they extend through a bolt opening in the lock pillar.

In order to allow good mobility with low friction in respect of the bolt, the bolt opening for the respective bolt is usually configured with a somewhat larger cross-sectional dimension than the bolt, so that the bolt, in its extended position, is accommodated with clearance in the bolt opening. In this way, a gap is formed between the bolt and the bolt opening. When the bolt is centred in the bolt opening, the gap extends all the way round the bolt. Typically, the cross section of the bolt and the bolt opening are polygonal, usually rectangular, but one or more of the sides of the bolt and of the bolt opening may also sometimes be curved, in which case the gap along the sides of the bolt receives a corresponding shape. Due to the effect of gravity upon the bolt, the bolt in its extended position may sometimes, at the lower part of the bolt opening, bear against the lock pillar, in which case the gap, when the bolt has a rectangular cross section, extends along three of the sides of the bolt. Furthermore, the fastening and coupling of the bolt to the lock mechanism can be configured with a certain clearance or play, so that the bolt is movable in its lateral directions . The gap on one side of the bolt can hence be made larger than the gap on the opposite side by pressing the bolt against this opposite side. In modern locks having such a locking device, the clearance between the bolt and the lock pillar at the bolt opening, in the cross-sectional plane of the bolt, is usually between around 0.2 and 0.5 mm.

One problem with known locking devices of this kind is that the clearance between the bolts and the lock pillar at the respective bolt opening allows a thin object to be inserted the gap which, due to the clearance, can be formed on either side of the bolt. By feeding a thin object of this kind through the gap, it may in certain cases be possible to tamper with or damage the lock mechanism in the lock housing. This problem is especially great in the case of outward- closing, non-rebated doors, in which a door chink which is accessible from the outside is formed between the lock pillar and the striking plate.

Prior art US 4,848,118 describes a lock containing a lock casing, a lock pillar having a bolt opening and a spring bolt extendable through the bolt opening and having laterally projecting pins which are accommodated in guide slots made in the lock casing. The spring bolt has four laterally projecting barrier walls arranged in front of the guide slots and inside the lock pillar. The purpose of the barrier walls is to prevent a lamellar tool which is fed in through the chink between the bolt and the lock pillar from being able to be fed in to the projecting pins with a view to actuating these for opening of the lock. The barrier walls provide good protection against such manipulation in those cases where a relatively thick and inflexible lamellar tool is used. It has been shown, however, that it is possible, through the use of thinner and more flexible lamellar tools, to get the tool to pass through the barrier walls and hence enable manipulation also of the parts found inside the barrier walls.

Summary of the invention

One object of the invention is to provide an improved locking device of the type defined in the introduction. Another object is to provide a locking device of this kind offering improved security. One more object is to provide a locking device of this kind in which manipulation of the lock by means of thin and easily flexible lamellar objects is made more difficult. Yet another object is to provide a locking device of this kind which is simple, reliable and functionally reliable.

These and other objects are achieved with a locking device of the kind which is defined in the preamble to Claim 1 and which has the distinguishing features defined in the characterizing part of the claim. The locking device comprises a lock mechanism, a lock pillar having at least one bolt opening, and at least one bolt . The bolt is mechanically coupled to the lock mechanism and is movable between a position retracted in the direction of the lock mechanism and a position extended through the bolt opening. The bolt has a blocking protrusion, which is disposed inside the lock pillar and projects in the lateral direction relative to the motional direction, and a front bolt portion, which is disposed in front of the blocking protrusion and, in the extended position, is accommodated in the bolt opening with a clearance to the lock pillar. According to the invention, the locking device comprises a covering element which is fixed in relation to the lock pillar and extends parallel with the motional direction of the bolt, which covering element has a first recess which, when the bolt is in the extended position, is disposed laterally outside the blocking protrusion and is open in the direction of the bolt .

The blocking protrusion is disposed inside the lock pillar and projects in one of the lateral directions of the bolt, at a level outside a corresponding side face of the front bolt portion. A lamellar object which is inserted into the gap between bolt and lock pillar formed by the clearance therebetween, hit against that face of the blocking protrusion which is facing towards the front bolt portion, and against the bolt opening. The blocking protrusion thus makes it to some extent more difficult to feed a lamellar object to vital lock parts disposed inside the blocking protrusion. By, for example, pre-bending ends of the lamellar object and imparting certain torsional motions to the object during the insertion, it may however be possible to get the ends of the object to slide in the direction away from the bolt along that face of the blocking protrusion which is facing towards the bolt opening. The object can hence be made to hit against the inner side of a side wall of the lock and, under guidance of the side wall, be led onward past the blocking protrusion into the lock mechanism or other lock parts vital to security. In this way, there is therefore a risk of manipulation of the lock even in such previously known locking devices which are provided with blocking protrusions on the bolt.

In a locking device according to the invention, the risk of such manipulation of the lock is substantially reduced. If the end of an object fed in through the gap between the bolt and the lock pillar, under the guidance of the blocking protrusion or otherwise, can be forcibly pushed laterally outwards away from the bolt, the end will be received by the recess disposed outside the blocking protrusion. This makes it substantially more difficult for the end, under guidance of the inner side of, for example, the side wall of the lock housing, to possibly be fed further in towards the vital parts of the lock.

Where the recess is constituted by a non-continuous depression in the covering element, the end of the object will be captured in the recess, whereupon the side limit faces of the recess prevent further feeding of the object along that side of the covering element which is facing towards the bolt.

The first recess is expediently, however, a first continuous opening disposed in the covering element. The end of the inserted object will hence pass out through the opening and, as the object continues to be fed in, is led onward on the outer side of the covering element. The covering element expediently extends past the lock mechanism and other vital lock parts, so that these parts disposed inside the covering element are protected from the object advanced outside the covering element.

The locking device can comprise a plate disposed outside the covering element provided with the first continuous opening, which plate extends substantially parallel with the covering element. The plate can be constituted, for example, by a side wall of a lock housing or a lock casing.

The plate can in this case bear against the outer side of the covering element . Where the recess in the covering element is a continuous opening through the covering element and the plate has no corresponding continuous opening, the opening covered by the plate forms a recess which captures the end of an inserted object.

The plate can alternatively be disposed at a certain distance from the outer side of the covering element, so that a gap in which the opening emerges is formed between the covering element and the plate. The gap thereby forms a channel which forcibly guides an object which has passed through the opening in the covering element. By ensuring that no vital lock parts are disposed in the channel, a very high security is thereby achieved.

The locking device can comprise a first recess, which is a first continuous opening, and a second recess, which is disposed in the plate, outside the first opening. Where the second recess is a non-continuous depression, there is obtained, together with the continuous opening in the covering element, a deeper depression for more secure capture of the end of the object. Where the second recess is a continuous opening made through the plate, a continuous opening through both the covering element and the plate is obtained, to allow the inserted object to be led off outside the plate.

The covering element can comprise a bar, fixed to the lock pillar, of generally L-shaped or U-shaped cross section. A bar of this kind can constitute, for example, a mounting base for other lock parts and components integral to the lock. In this way, an effective modular construction system for the locking device is made possible.

The covering element can alternatively comprise a cover plate constituting a side wall of a lock housing which is fixed to the lock pillar. A pre-existing side wall of the lock is here used to increase security against manipulation through the use of lamellar objects.

The blocking protrusion disposed on the bolt expediently has an undercut which is open in the direction of the front bolt portion. By undercut is here meant that the face of the blocking protrusion which is facing towards the front bolt portion is shaped such that a space or a pocket is formed between this face and that face of the bolt which adjoins the blocking protrusion. By virtue of the undercut of the blocking protrusion, a lamellar object which is fed in along the front bolt portion will be received and caught by the pocket formed by the undercut. It is thereby made substantially more difficult, even with very thin, easily flexible and bent lamellar objects, to make the end of the object slide along the front face of the blocking protrusion to allow passage outside the blocking protrusion.

The locking device can further comprise a blocking element which is disposed, such that it is limitedly displaceable in a plane lying non-parallel with the motional direction of the bolt, between the lock pillar and the blocking protrusion. The blocking element constitutes an inner barrier for lamellar objects which have been fed in through the gap formed between the bolt and the bolt opening in the lock pillar. The mobility of the blocking element non-parallel to the motional direction of the bolt means that the blocking element, during the movement of the bolt between the retracted and the extended position, can follow irregularities in the face of the bolt, as well as lateral movements of the bolt which may result from asymmetries and biases in the mounting and guidance of the bolt. The blocking element can hence either be arranged bearing against the bolt, or with only a small clearance thereto. Where the blocking element bears against the bolt, the blocking element constitutes an inner barrier for all objects inserted into the gap between the bolt and the lock pillar. Where the blocking element is arranged with a certain small clearance to the bolt, the blocking element constitutes an inner barrier for such lamellar objects which are thinner than the gap between the bolt and the lock pillar, but thicker than the clearance between the blocking element and the bolt. Since this clearance, by virtue of the mobility of the blocking element, can be made very small, the risk of lamellar objects being fed past the blocking element in towards the lock mechanism is correspondingly reduced.

The blocking element expediently comprises a blocking plate having an opening which surrounds the bolt. The displacement of the blocking element in the direction away from as well as towards the bolt will hence be driven by the contact between the sides of the bolt and the respective opposite edge of the continuous opening in the blocking element, in which opening the bolt is accommodated. This embodiment offers, inter alia, the advantage that there is no need for any additional elements for pressing the blocking element in the direction of the bolt. In order to avoid friction between the bolt and the blocking element, the opening in the blocking element should be configured such that a certain small clearance is formed between the bolt and the blocking element. By virtue of the mobility of the blocking element transversely to the motional direction of the bolt, this clearance can, however, be essentially much smaller than the clearance between the bolt and the lock pillar. Further objects and advantages of the locking device according to the invention emerge from the following detailed description of illustrative embodiments and from the patent claims .

Brief description of the figures

Illustrative embodiments of the invention are described below with reference to the figures, whereof:

Fig. 1 is a perspective view of a first embodiment of a locking device according to the invention,

Fig. 2 is a perspective view corresponding to that of Fig. 1, with certain components removed,

Fig. 3 is a simplified schematic sectional view from above of the locking device shown in Figs. 1 and 2,

Fig. 4 is a simplified schematic sectional view corresponding to that in Fig. 3 and shows a locking device according to a second embodiment of the invention,

Fig. 5 is a simplified schematic sectional view corresponding to that in Fig. 3 and shows a locking device according to a third embodiment of the invention,

Fig. 6 is a simplified schematic sectional view corresponding to that in Fig. 3 and shows a locking device according to a fourth embodiment of the invention,

Fig. 7 is a simplified schematic sectional view corresponding to that in Fig. 3 and shows a locking device according to a fifth embodiment of the invention. Detailed description of illustrative embodiments Figs. 1, 2 and 3 show a locking device according to the invention, which is configured for recessed fitting in a door leaf . The locking device comprises a lock pillar 1, to which a lock housing 2 having a first 31 and a second side wall 32 is fixed. As can most clearly be seen from Figs . 2 and 3 , the locking device comprises a U-bar 4, which is fixed to the lock pillar 1 and to which the side walls 3a, 3b of the lock housing are fixed. The lock housing 2 accommodates a lock mechanism, which, inter alia, comprises a cylinder rower 5 and a handle rower 6 for operation of the lock mechanism. A spring bolt 7 is coupled to the lock mechanism and is axially movable in a straight line through a spring bolt opening 8 made through the lock pillar 1.

A bolt 10 in the form of a swing bolt is also coupled to the lock mechanism and is pivotably movable through a rectangular bolt opening 9 made in the lock pillar 1.

Fig. 3 constitutes a schematic sectional view from above and shows certain of the parts integral to the locking device shown in Figs . 1 and 2. As can be seen from Fig. 3, the U-bar 4 comprises a bottom part 41 and two side members 42, 43, which each form a covering element fixed to the lock pillar and extending parallel with the motional direction of the bolt. The bottom part 41 is fixed to the lock pillar 1 and has a bolt opening 44. The two side walls 31, 32 are formed of plates which are fixed on the outer side of the respective side member 42, 43 of the U-bar 4 and which extend parallel with the side members up to mutually opposite sides of the bolt 10.

The bolt 10 is movable between a position retracted in the lock housing and the extended position shown in Figs. 1-3. The bolt 10 comprises a front bolt portion 11, which in the extended position extends through the bolt openings 9, 44. The cross section of the front bolt portion 11 is rectangular. The bolt opening 9 in the lock pillar 1 has a corresponding rectangular shape, the height and width of which are somewhat greater than the height and width of the just mentioned cross section of the front bolt portion 11. The clearance between the front bolt portion 11 and the bolt opening 9 is around 0.2-0.5 mm in the vertical and lateral directions. The bolt opening 44 in the U-bar 4 is somewhat larger than the bolt opening 9 in the lock pillar 1. When the bolt 10 is centred in the bolt opening 9 of the lock pillar, a circumferential gap S is thereby formed between the front bolt portion 11 and the lock pillar 1. Correspondingly, at the bolt opening 44 of the U-bar, a circumferential gap S' is formed between the front bolt portion 11 and the bottom part 41 of the U-bar 4. The gap S' is somewhat larger than the gap S.

The bolt 10 comprises a bearing pin 12, which is accommodated in the side members 42, 43 of the U-bar 4 and defines a rotational axis A about which the bolt is pivotably mounted for displacement between the retracted and the extended position. A control pin 13 is disposed on the bolt 10 and is coupled to the lock mechanism (not shown) in order to control the movement of the bolt 10. The control pin extends through guide slots (not shown) made in the side members 42, 43 of the U-bar 4.

The bolt 10 has a first 14 and a second 15 blocking protrusion. The first blocking protrusion 14 projects laterally from the plane defined by a first side 11a of the front bolt portion 11. This first side 11a of the front bolt portion 11 is parallel with the motional direction of the bolt and with the longitudinal direction of the lock pillar 1. When the locking device is fitted in a door (not shown) by customary recessed fitting, the first side 11a is a vertical side which is parallel with and facing towards the outer side of the door. The second blocking protrusion 15 projects correspondingly from a second side lib of the front bolt portion 11. This second side lib is opposite to the first side lla and thus, in the fitted position, is parallel with and facing towards the inner side of the door.

A first pair of continuous openings 51, 52 is made in the respective side member 42, 43. A second pair of continuous openings 53, 54 are made in the respective side wall 31, 32. The openings 51 and 53 overlap each other and are arranged laterally outside the blocking protrusion 14 and a portion, adjoining the blocking protrusion, of the first side lla of the front bolt portion 11. The openings 52 and 54 correspondingly overlap each other and are arranged laterally outside the blocking protrusion 15 and a portion, adjoining the blocking protrusion, of the second side lib of the front bo].t portion 11. In this way, the openings 51 and 53 together form an opening extending continuously through the side member 42 and the side wall 31. Correspondingly, the openings 52 and 54 together form an opening extending continuously through the side member 43 and the side wall 32. As can be seen from Fig. 3, those edges of the openings 51-54 which are distal to the lock pillar 1 are bevelled such that the openings, at these edges, are widened outwards in the direction away from the bolt 10.

If a lamellar object is fed in through the gaps S and S' on the first side lla of the front bolt portion 11, and further inwards so that this front end hits against that face 14a of the blocking protrusion 14 which is facing towards the lock pillar 1, the end, with the aim of passing the blocking protrusion, can be made to slide in the direction outwards along the face 14a. As the object continues to be fed in, the end, while a portion of the object following on from the end comes to bear against the blocking protrusion 14, will be guided in the direction outwards towards the inner side of the side member 42. By virtue of the openings 51, 53 made in the side member 42 and the side wall 31, the end will not be able to rest against the inner side of the side member 42 with the aim of being guided onwards towards the control pin 13 situated inside the side member 42 and behind the blocking protrusion 14, or other vital lock parts. The end of the object will instead pass out through the openings 51, 53 to the outer side of the locking device, from where manipulation of the lock is not possible.

In Fig. 4, an alternatively simplified embodiment, in which the U-bar has been dispensed with, is illustrated schematically. In this embodiment, the side walls 131,

132 are fixed in the lock pillar 101. Continuous openings 153 and 154 are made in the side walls 131 and

132 laterally outside the blocking protrusions 114 and 115, respectively. In this simplified embodiment, the openings 153, 154 function correspondingly to the openings 51-54 in the embodiment shown in Figs. 1-3.

In Fig . 5 , another embodiment of the locking device according to the invention is illustrated schematically. As in the embodiment illustrated in Fig.

3, this locking device comprises a U-bar 204 having a bottom part 241, which is fixed to the lock pillar 201, and two side members 242, 243, which project rearwards from the bottom part. A bolt opening 244 is made in the bottom part 241 of the U-bar. Two side walls 231, 232, which are formed of plates, are fixed to the outer side of a respective side member 242, 243 of the U-bar 4 and extend parallel with and in bearing contact with the side members 242, 243 up to mutually opposite sides of the bolt 10.

A continuous opening 251, 252 is made in each of the side members 242, 243, laterally outside the respective blocking protrusion 214, 215 and a part of the portion, adjoining the blocking protrusion, of the respective side 211a, 211b of the front bolt portion 211. Unlike the embodiment shown in Fig. 3, in this embodiment the side walls 231, 232 do not however have any recess overlapping the openings 251, 252 in the side members 242, 243. The continuous openings 251, 252 thereby form together with the side walls 231, 232 non-continuous recesses, which are open in the direction of the bolt 210, in the side members 242, 243 and the side walls 231, 232.

The bolt 210 has a first 214 and a second 215 blocking protrusion, which project in the lateral direction relative to the front bolt portion 211. That part of the first blocking protrusion 214 which lies adjacent to the front bolt portion 211 is provided with a first undercut 220. The undercut 220 is formed by a flat face facing towards the front bolt portion 211, which face is slanted in relation to the first side 211a of the front bolt portion. In this way, the undercut 220 forms and delimits a first space 220a or a pocket between the first blocking protrusion 214 and that part of the bolt 210 from which the first blocking protrusion 214 projects. The first space 220a is open in the direction of the front bolt portion 211.

Correspondingly, the second blocking protrusion 215 is provided with a second undercut 221, which is formed by a flat face facing towards the front bolt portion 211, which face is slanted in relation to the second side 211b of the front bolt portion. The second undercut 221 forms and delimits a second space 221a or pocket, which is open in the direction of the front bolt portion 211.

In the event of a manipulation attempt, a thin and easily flexible lamellar object (not shown) can be fed in through the door chink from the outer side of the door and further in through the gaps S and S' on the first side 211a of the front bolt portion, and thereafter onward along the first side inwards into the lock. By virtue of the first undercut 220 disposed on the first blocking protrusion 214, the inserted end of the object will hit, however, against the oblique face of the first undercut. As the end of the object is fed in further, this will be forcibly guided to slide along the face of the first undercut 220 until the end thereof reaches the bottom of the first space 220a, where the oblique face of the undercut 220 is joined to the side face of the bolt 210 from which the first blocking protrusion 214 projects. In this way, the end of the lamellar object is caught in the first space 220a and prevented from sliding along the blocking protrusion 214 in the lateral direction outwards from the plane defined by the first side 211a of the bolt portion 211. The end of the lamellar object is here prevented from being steered towards, for example, the control pin 213 or other parts of the lock which are prone to manipulation. Manipulation through the insertion even of very thin and easily flexible objects is thereby deterred in a secure, simple and functionally reliable manner.

Should a lamellar or other object nevertheless be able to be steered in the lateral direction outwards from the side face 211a of the front bolt portion 211, the end of the object will be received and caught by the recess formed by the opening 251. The advancement of the object along the inner side of the side member 242 in the direction of the control pin 213 and other vital lock parts disposed behind the blocking protrusion is thereby deterred. As can be seen from Fig. 5, that edge of the opening 251 which is distal to the lock pillar 201 is bevelled. As a result, an undercut is formed in the recess formed by the opening 251. This undercut is suitable for capturing and detaining that end of a lamellar object which is received in the recess and thereby makes further advancement of the object in the direction of the vital parts of the lock more difficult.

The locking device illustrated in Fig. 6 conforms in large part to the embodiment described above and illustrated in Fig. 4. In the locking device shown in Fig. 6, the two side walls 331, 332 are arranged, however, at a certain distance from the side members 342, 343 such that a gap is formed between the respective side member 342, 343 and side wall 331, 332. The continuous openings 351, 352 made in the side members 342, 343 emerge respectively in one of these gaps 361, 362.

Hence, in this embodiment, a lamellar object whose end is received in one of the openings 351, 352 will be led out in the corresponding gap 361, 362 and is there led onward outside the side member 342, 343, from where it cannot make contact with any vital lock part. Security against manipulation through the insertion of lamellar objects through the gap S between the bolt 210 and the lock pillar 201 is thereby further increased.

In Fig. 7, a further embodiment is illustrated. In this embodiment, the locking device comprises a lock pillar 401 having a bolt opening 409. Side walls 431, 432 are fixed to the lock pillar 401. The locking device further comprises a blocking element in the form of a blocking plate 470. The blocking plate 470 is accommodated, such that it is displaceable in a controlled manner, in continuous slots 471, 472 disposed in the side walls 431, 432. The blocking plate 470 is thereby disposed between the lock pillar 401 and the control pin 413. The blocking plate 470 can hence be moved to and fro in a direction perpendicular to the motional direction of the bolt 410. The width of the slots 471, 472 in the side walls 431, 432, parallel with the motional direction of the bolt, is only somewhat greater than the thickness of the blocking plate 470. The blocking plate is hence substantially- prevented from moving in a direction to and from the lock pillar 401. The blocking plate 470 has a continuous opening 473 with a shape corresponding to the cross section of the front bolt portion 411. The fact that the blocking plate can move in the lateral directions of the bolt means that the clearance between the blocking plate 470 and the front bolt portion 411 is made substantially smaller than corresponding clearance between the lock pillar 401 and the front bolt portion 411 at the bolt opening 409 through the lock pillar 401. The maximum gap S'' between the front bolt portion 411 and the blocking plate 470 is hence smaller to a corresponding degree than the gap S between the front bolt portion 411 and the lock pillar 401. It will further be appreciated that the blocking plate 470 is free to move by a small distance to and fro perpendicularly to the plane defined by the motional direction of the bolt, which distance is defined by the clearance between the bolt 410 and the blocking plate 470.

The fact that the clearance between the blocking plate 470 and the bolt 410 can be made very small means that the blocking plate 470 thereby constitutes an inner barrier for lamellar objects which are fed in through the gap S between the bolt and the lock pillar 401. Lamellar objects which are sufficiently thin to pass through the gap S but thicker than the very narrow gap S' ' are thereby prevented from being fed further into the locking device, for example to the control pin 413 or other vital lock parts in an attempt to manipulate these .

In the locking device shown in Fig. 7, the side walls 431, 432 have continuous recesses 453, 454, 455, 456. A first pair of recesses 453, 454 is made in the side walls 431, 432 laterally outside the blocking protrusions 414, 415. A second pair of recesses 455, 456 is made in the side walls 431, 432 laterally outside that portion of the bolt 410 which, in its extended position, is found between the blocking plate 470 and the lock pillar 401.

If a lamellar object which is fed in through the gap S between the bolt 410 and the lock pillar 401 and is thereafter guided in the lateral direction away from the bolt, the end of the object will pass out through the corresponding recess 455, 456 in the second pair of recesses. The risk of the lamellar object in contact with the inner side of the side walls 431, 432 being able to be led back towards the bolt 410 and thus making its way in through the gap S' ' between the bolt 410 and the blocking plate 470 is thereby reduced. Should a lamellar object nevertheless be able to be fed in through the gap S' ' between the bolt 410 and the blocking plate 470, and thereafter be able, despite undercuts 420, 421 on the blocking protrusions 414, 415, to be guided in a lateral direction outwards from the bolt 410, the inserted end of the object will pass out through a respective opening of the first pair of openings 453, 454. Access to any one of the vital lock parts situated behind the blocking protrusions 414, 415 and inside the side walls 431, 432 is thereby made yet more difficult.

Above, various illustrative embodiments of the locking device according to the invention have been described. It will be appreciated, however, that the invention is not limited to these embodiments, but rather can be freely varied within the scope of the following patent claims. For example, the bolt, instead of being constituted by a swing bolt, can be constituted by any other type of bolt which is displaceable between a retracted position and a position extended through a bolt opening in a lock pillar. Examples of such alternative bolts are linearly and axially movable bolts, wedge bolts, spring bolts, locking bolts and combined latches and bolts which usually belong under the term "latchbolts" . It will further be appreciated that various characteristics of the locking device according to one particular embodiment can also be combined with a locking device according to any of the other embodiments.

Claims

Patent claims

1. Locking device comprising - a lock mechanism,

- a forend (1, 101, 201, 301, 401) having at least one bolt opening (9, 109, 209, 309, 409) and

- at least one bolt (10, 110, 210, 310, 410), which is mechanically coupled to the lock mechanism and is movable between a position retracted in the direction of the lock mechanism and a position extended through the bolt opening, and which has a blocking protrusion (14, 15, 114, 115, 214, 215, 314, 315, 414, 415) disposed inside the forend and projecting in the lateral direction relative to the motional direction, and a front bolt portion (11, 111, 211, 311, 411) disposed in front of the blocking protrusion and, in the extended position, accommodated in the bolt opening with a clearance to the forend, characterized by a covering element which is fixed in relation to the forend and extends parallel with the motional direction of the bolt, which covering element has a first recess which, when the bolt is in the extended position, is disposed laterally outside the blocking protrusion and is open in the direction of the bolt.

2. Locking device according to Claim 1, in which the first recess is a first through opening (51, 52, 153, 154, 251, 252, 453, 454) .

3. Locking device according to Claim 1 or 2 , comprising a plate disposed outside the covering element provided with the first through opening, which plate extends substantially parallel with the covering element.

4. Locking device according to Claim 3 , in which the plate bears against the outer side of the covering element .

5. Locking device according to Claim 3 , in which the plate is disposed at a certain distance from the outer side of the covering element, so that a gap (361, 362) in which the opening (351, 352) emerges is formed between the covering element and the plate .

6. Locking device according to any one of Claims 3-5, in which the first recess is a first through opening (51, 52) and a second recess is disposed in the plate, outside the first opening.

7. Locking device according to any one of Claims 1-6, in which the covering element comprises a bar (4, 204, 304) , fixed to the forend, of generally L-shaped or U-shaped cross section.

8. Locking device according to any one of Claims 1-6, in which the covering element comprises a cover plate constituting a side wall (131, 132, 431, 432) of a lock housing which is fixed to the forend (101, 301) .

9. Locking device according to any one of Claims 1-8, in which the blocking protrusion (214, 215, 314, 315, 414, 415) disposed on the bolt has an undercut (220, 221, 320, 321, 420, 421) which is open in the direction of the front bolt portion (211, 311, 411) .

10. Locking device according to any one of Claims 1-8, comprising a blocking element which is disposed, such that it is limitedly displaceable in a plane lying non-parallel with the motional direction of the bolt (410) , between the forend (401) and the blocking protrusion (414, 415) .

11. Locking device according to Claim 10, in which the blocking element comprises a blocking plate (470) having an opening (473) which surrounds the bolt (410) .