DOOR LOCK WITH A HOOK BOLT

Abstract: A door lock, comprising a housing-like lock case (1) provided with a front plate (3) and including a hook bolt (4;5,6), which is movable between a locking and a releasing position by means of a key (9) of the lock or other force transmission element and comprises a linearly movable guiding part (5) and a separate hook part (6) turnably journalled on the end thereof and which is arranged in cooperation with a striking plate (14) in a door frame (13) so that in its locking position the hook part (6) of the hook bolt (4; 5, 6) is moved through an opening (14a) in the striking plate and is turned towards an inner surface (14b) in the striking plate. The hook bolt (4; 5, 6) comprises a pivot arrangement by means of which the hook part (6) is movable with regard to the guiding part (5) in the longitudinal direction of the front plate (3). In addition the lock case (1) includes a guiding groove (8; 8a, 8b) for guiding the pivoting point of the hook part (6) both in the longitudinal direction of the front plate (3) and in the direction of movement of the guiding part (5).

Description: DOOR LOCK WITH A HOOK BOLT The invention relates to a door lock provided with a hook bolt in accordance with the preamble of claim 1 . The Finnish patent 1 041 99 discloses a door lock of the kind meant above, in which a separate hook part of a hook bolt is turnably journalled to a guide part movable in the lock case. An aim of the invention is to further develop lock arrangements for a door or other turnable wings provided with a hook bolt so that the possibilities for installation of this kind of locks would be more extensive and their burglary preventing properties would further be improved. A further aim of the invention is that the lock would be secure as to the operation and advantageous as to its costs. The aims of the invention can be met as is more closely disclosed in claim 1 and in the other claims. According to the invention the hook bolt comprises a pivot arrangement by means of which the hook part is movable with regard to the guiding part in the longitudinal direction of the front plate. In addition the lock case includes a guiding groove for guiding the pivoting point of the hook part both in the longitudinal direction of the front plate and in the direction of movement of the guiding part. This makes it possible to move the hook part inside the striking plate so that the hook part can turn into its locking position in a smaller space than before. Hereby it is possible to essentially reduce the requirement for space in the direction of the movement of the guiding part and the protruding length of the bolt, whereby possibilities for installation of the lock in different locations can correspondingly be increased. In practice the pivot arrangement of the hook part is accomplished by means of a pivot pin, which is movably supported to a guiding groove arranged in the guiding part and extending mainly in the longitudinal direction of the front plate. The shape of the guiding groove in the lock case is with advantage selected so that in the first phase of the movement of the hook bolt out into the protruding position the pivoting point of the hook part is moved at the same time downwards with regard to the front plate. When the hook part is moved out from the opening for the bolt in the front plate, the guiding groove extends substantially only in the direction of the movement of the guiding part. In order to secure the turning movement of the hook part into the locking po- sition the lock case includes a guiding surface which, after the hook part is moved through the opening for the bolt in the striking plate, is arranged to guide the hook part so that it is turned with regard to its pivoting point inside the striking plate into its locking position. In order to improve burglar-proof properties of the lock and especially to prepare for a situation where one tries to lift the entire door provided with the lock away from its hinges by making use of the hook bolt, at the front plate side end of the guiding groove in the lock case at the position corresponding to the locking position of the hook part there is an extension part in the guiding groove extending upwards in the longitudinal direction of the front plate and separated from the guiding groove by means of a connection piece. This connection piece is with advantage fixed to the lock case through shallow parts, which can be broken with said pivot pin. Correspondingly the upper surface of the hook part includes a recess which is arranged in coopera- tion with the upper edge of the opening for the bolt in the front plate to prevent moving of the hook bolt inside the lock case after said connection piece is broken by means of said pivot pin. As a consequence of these measures the hook bolt remains fully jammed as a result of an attempted burglary and thus the attempted burglary utilizing said technique is effectively stopped. In order to secure the preventing measures mentioned above the hook part is additionally so dimensioned that in its fully protruding locking position it fills the major part of the opening of the striking plate in the longitudinal direction of the front plate. For its part this prevents already as such moving of the door out from its hinges. The construction of the bolt can be kept simple and secure as to its operation when the guiding part of the hook bolt is continuously located inside the lock case. In the following the invention is described as a way of example with refer- ence to the attached drawing, in which Fig. 1 shows a side view of a known door lock arrangement installed in a door and the lock case opened, Figs. 2-9 show an embodiment of a door lock according to the invention in different operating positions of the hook bolt. The known door lock shown in figure 1 comprises a lock case 1 , which is provided with a front plate 3, by means of which it is fixed to a door 2 or the like. The lock includes a hook bolt 4, which comprises a guiding part 5, which is linearly movable inside the lock case and to which a hook part 6 of the hook bolt is turnably journalled by means of a pivot pin 7. The lock case comprises also a guiding groove 8, which guides the pin 7 and thus the movements of the hook bolt. The hook bolt 4 is moved directly by means of a key 9 of the lock. In addition the lock includes a set of spring-loaded locking discs 10 movable with the key 9 of the lock and including a locking channel 1 1 for a lock pin 1 2 fixed to the guiding part 5 of the hook bolt. The operation of the lock as such is quite conventional and is described for instance in said Finnish patent 1 041 99, so it is not here described in more detail. Figure 1 shows also a striking plate 1 4 for the lock fixed to a door frame 1 3 or the like and including a housing 1 5 for the bolt. In figure 1 the hook bolt 4 is in its protruding locking position, in which the hook part 6 has entered through an opening 3a for the bolt in the front plate and through an opening 14a for the bolt in the striking plate into the housing 1 5 so that the hook part 6 extends some length parallel with an inner surface 1 4b in the striking plate. The arrangement according to the invention illustrated in figures 2-9 differs from the known arrangement of figure 1 in the first place so that in accordance with the invention when the hook bolt is moved from the withdrawn position into its protruding locking position the hook part 6 of the hook bolt is arranged to move in successive order in opposite turning directions relative to the guiding part 5 at the same time as the pivoting point of the hook part is moved in the direction of the front plate. Hereby the space required for the turning of the hook part of the hook bolt can be reduced and the protruding length of the bolt can be essentially shortened without compromising the security of locking and operation of the arrangement. In practice this is accomplished so that also in this case the hook part 6 of the hook bolt is turnably journalled to the guiding part 5 by means of the pivot pin 7, but the pivot pin 7 can move in a guiding groove 5a arranged in the guiding part and extending in the longitudinal direction of the front plate 3. In addition the guiding groove 8 in the lock case includes two branches 8a and 8b extending in different directions. The first branch 8a is transverse with both the direction of movement of the guiding part 5 of the hook bolt and the front plate 3. As a consequence of this when the hook bolt is moved outwards from the lock case the hook part 6 is at the same time turned somewhat in clockwise direction relative to the guiding part 5 (figure 3). The second branch 8b extends in the direction of the movement of the guiding part 5, so when the hook bolt is moved further the hook part 6 moves at the same time through both the opening 3a for the bolt in the front plate and the opening 1 4a for the bolt in the striking plate (the latter is not shown; figure 4). Now the hook part 6 can turn by means of the pivot pin 7 in counter- clockwise direction with regard to the guiding part 5 into its locking position, which occurs partly due to gravity and partly due to guiding surfaces 6b in the hook part and 1 7 in the lock case respectively (figures 5 and 6). In accordance with the invention the guiding groove 8 in the lock case includes further an extension part 8c, which extends upwards in the direction of the front plate 3 and which is normally separated from the branch 8b by means of a connection piece 1 6, which is fixed to the lock case through shallow parts 1 6a. The shallow parts 1 6a are so dimensioned that if a lifting force acts on the lower edge of the hook part 6 for instance in the pursuit to lift the door out from its hinges, the pivot pin 7 of the hook part 6 breaks the shallow parts 1 6a at the same time as the pin 7 is moved on one hand along the guiding groove 5a in the guiding part and on the other hand along the extension part 8c of the guiding groove in the lock case upwards in the figures. This is illustrated in figures 7 and 8. Moving of the door out from its hinges as such will fail since the hook part 6 is dimensioned with regard to the opening 1 4a for the bolt in the striking plate so that the construction does not allow an upward movement long enough. As a consequence of this movement, however, the entire hook bolt is jammed due to a recess 6a made in the hook part 6 and being in cooperation with the upper edge of the opening 3a for the bolt in the front plate. A bevel surface in the recess 6a together with the pivot pin 7, the broken connection piece 1 6 and the guiding grooves 5a and 8c act in a wedge-like manner on the hook part 6 preventing hereby effectively any further measures for this part (figure 9). Hereby damaging of other inner members of the lock by means of the bolt can also be prevented, whereby the requirements for strength for their part can correspondingly be kept lower and thus the manufacturing costs for the lock case itself can be kept lower as well. It is to be noted that the hook bolt arrangement according to the invention can be applied in different lock cases independent on whether the move- ments of the bolt are carried out directly through a key, a key operated locking mechanism or for instance through an electric or electromagnetic arrangement. In addition to doors the lock can naturally be installed also to cor- responding lockable locations such as hatches, turnable wings etc. Thus, the invention is not limited to the embodiment shown but several modifications are feasible within the scope of the attached claims.

Claims: CLAIMS 1 . A door lock, comprising a housing-like lock case (1 ) provided with a front plate (3) and including a hook bolt (4;5,6), which is movable between a locking and a releasing position by means of a key (9) of the lock or other force transmission element and comprises a linearly movable guiding part (5) and a separate hook part (6) turnably journalled on the end thereof and which is arranged in cooperation with a striking plate (1 4) in a door frame (1 3) so that in its locking position the hook part (6) of the hook bolt (4;5,6) is moved through an opening (1 4a) in the striking plate and is turned towards an inner surface (1 4b) in the striking plate, characterized in that the hook bolt (4;5,6) comprises a pivot arrangement by means of which the hook part (6) is movable with regard to the guiding part (5) in the longitudinal direction of the front plate (3), and in that the lock case (1 ) includes a guiding groove (8;8a,8b) for guiding the pivoting point of the hook part (6) both in the longitudinal direction of the front plate (3) and in the direction of movement of the guiding part (5) . 2. A door lock according to claim 1 , characterized in that the pivot arrange- ment of the hook part (6) is accomplished by means of a pivot pin (7), which is movably supported to a guiding groove (5a) arranged in the guiding part (5) and extending mainly in the longitudinal direction of the front plate (3). 3. A door lock according to claim 1 or 2, characterized in that the shape of the guiding groove (8;8a,8b) in the lock case is selected so that in the first phase of the movement of the hook bolt (4) out into the protruding position the pivoting point (7) of the hook part (6) is moved at the same time downwards with regard to the front plate (3). 4. A door lock according to any one of the preceding claims, characterized in that the shape of the guiding groove (8;8a,8b) in the lock case is selected so that when the hook part (6) is moved out from an opening (3a) for the bolt in the front plate the guiding groove (8;8a,8b) extends substantially only in the direction of the movement of the guiding part (5). 5. A door lock according to any one of the preceding claims, characterized in that the lock case includes a guiding surface (1 7) which, after the hook part (6) is moved through the opening (14a) for the bolt in the striking plate, is arranged to guide the hook part (6,6b) so that it is turned with regard to its pivoting point (7) inside the striking plate (1 4) into its locking position. 6. A door lock according to any one of the preceding claims, characterized in that at the front plate (3) side end of the guiding groove (8;8a,8b) in the lock case at the position corresponding to the locking position of the hook part (6) there is an extension part (8c) in the guiding groove extending upwards in the longitudinal direction of the front plate (3) and separated from the guiding groove (8;8a,8b) by means of a connection piece (1 6), and in that said connection piece (1 6) is fixed to the lock case (1 ) through shallow parts ( 1 6a) which can be broken with said pivot pin (7). 7. A door lock according to claim 6, characterized in that the upper surface of the hook part (6) includes a recess (6a) which is arranged in cooperation with the upper edge of the opening (3a) for the bolt in the front plate to prevent moving of the hook bolt (4) inside the lock case after said connection piece (1 6) is broken by means of said pivot pin (7). 8. A door lock according to any one of the preceding claims, characterized in that the hook part (6) is so dimensioned that in its fully protruding locking position it fills the major part of the opening (14a) of the striking plate in the longitudinal direction of the front plate (3) preventing thereby moving of the door out from its hinges. 9. A door lock according to any one of the preceding claims, characterized in that the guiding part (5) of the hook bolt is continuously located inside of the lock case (1 ).

Inventors: HAAPANIEMI JOUNI, LINDSTROEM MARKO, PAASONEN SIMO, HAAPANIEMI, JOUNI, LINDSTROEM, MARKO, PAASONEN, SIMO
Applicants: BJOERKBODA LAAS OY AB, HAAPANIEMI JOUNI, LINDSTROEM MARKO, PAASONEN SIMO, HAAPANIEMI, JOUNI, LINDSTROEM, MARKO, PAASONEN, SIMO
Application year: 2001
Main classification: E05B63
IPC codes: E05B63