Arrangement for guiding the deadlocking of a latch bolt in a door lock

A door lock includes a latch bolt and an auxiliary bolt. A stop member is supported by the auxiliary bolt and is movable relative to the auxiliary bolt between a position in which it prevents a guide element moving to a position providing deadlocking of the latch bolt, while the auxiliary bolt is in a protruding position, and a position in which it allows the guide element to move to a position providing the deadlocking of the latch bolt. The stop member allows the guide element to move to the position providing deadlocking of the latch bolt only in case both the auxiliary bolt and the latch bolt are first moved to retracted positions.

This is a national stage application filed under 35 USC 371 based on International Application No. PCT/FI2004/000255 filed Apr. 27, 2004, and claims priority under 35 USC 119 of Finnish Patent Application No. 20030719 filed May 14, 2003.

The invention relates to an arrangement for guiding the deadlocking of a latch bolt in a door lock.

A door lock provided with a latch bolt and an auxiliary bolt of the type discussed herein is disclosed in the Finnish patent specification FI 83802 C. The deadlocking of the latch bolt in this kind of door locks is accomplished simply by pressing the auxiliary bolt into the lock case. Normally this takes place when the door is being pushed to a closed position, whereby also the auxiliary bolt, in addition to the latch bolt itself, is retracted into the lock case urged by the doorframe and the striker plate thereon. When the door is in the closed position the latch bolt extends out into the opening in the striker plate of the lock, but the striker plate prevents the protrusion of the auxiliary bolt until the deadlocking of the latch bolt is released and the door is opened again. The deadlocking may be released in a way known per se, for instance by a door handle on the inside of the door, by a key, or by electrical remote control.

When the door is open, both the latch bolt and the auxiliary bolt are in their protruding positions in the above-discussed lock. If the auxiliary bolt is then pressed into the lock case either by accident or in case of misbehaviour, it activates simultaneously the deadlocking of the latch bolt, whereby the door cannot be closed simply by pushing, but one of the above-mentioned ways to release the deadlocking needs to be applied. Depending on the situation this can be fairly difficult, especially if the door is a public door used in daytime and in addition, it is electrically remote-controlled, whereby the signal reporting the malfunction is not necessarily immediately transmitted further.

An object of the invention is to provide a novel arrangement, the construction of which is as uncomplicated and reliable as possible and by means of which the above-described malfunction can be eliminated efficiently.

According to the invention the arrangement includes members which are arranged so as to allow the moving of a guide element to a position providing the deadlocking of the latch bolt only in case both the auxiliary bolt and the latch bolt are first moved to their retracted positions. Thus the pressing of the auxiliary bolt in is not alone enough for activating the deadlocking of the latch bolt, but it will take place only after the door has been pushed to its closed position and both the latch bolt and the auxiliary bolt are retracted into the lock case urged by the door frame.

In a preferred practical embodiment said members include a separate stop member supported movably by the auxiliary bolt, which stop member is arranged to act upon the guide element, for instance a protrusion in it, so that it prevents the moving of the guide element to its position providing the deadlocking of the latch bolt, when the auxiliary bolt is in its protruding position. Thus said stop member can with advantage be arranged to be moved to a position, where it allows the moving of the guide element to a position providing deadlocking of the latch bolt. In order to secure the operation of the stop member it is urged by spring to its said position allowing the moving of the guide element.

The auxiliary bolt is preferably provided with a guiding piece attached to the lock case, which guiding member defines the freedom of movement of the stop member and is arranged to guide the movements of the auxiliary bolt. The stop member preferably comprises a guiding edge, which is in cooperation with the guide element and is turnable relative to said guiding piece. The guiding piece comprises wedge-shaped guide surfaces for the stop member, whereby they preferably define the turning freedom of the stop member.

The protrusion of the guide element is with advantage provided with a recess, where the stop member is normally located so that it prevents said turning movement of the stop member, while the latch bolt and the auxiliary bolt are in their protruding positions. Thus no separate stoppers are required for guiding the operation of the stop member itself.

The latch bolt may be provided with a guide surface, which is arranged to move the guide element so as to release the stop member from the impact of said recess, when the latch bolt is being pressed into the lock case. In a preferred practical embodiment said guide surface may be connected to the deadlocking member of the latch bolt, which member the guide element is arranged to act upon in order to accomplish deadlocking of the latch bolt.

The invention may preferably be applied to a lock case, which has also a dead bolt, just as is disclosed in the above-mentioned patent specification FI 83802 C. In that case said guide element is preferably arranged to guide also the movements of the dead bolt.

In the drawings the reference numeral1indicates a lock case to be installed in a door or the like, which lock case is provided with a front plate2, and has a latch bolt3and an auxiliary bolt8as well as a guide element7operatively connected to these. In the embodiment according to the figures the lock case is further provided with a dead bolt13, which is conventional as such, but the invention may be applied independently of the dead bolt.

The latch bolt3is of the type that it enables the opening and closing of the door without separate operational means so that the latch bolt is pressed to its retracted position in the lock case, when either wedge side of the tapering wedge-shaped end of the latch bolt protruding from the lock case hits the striker plate of the lock on the door frame. The latch bolt3according to the shown embodiment comprises a body part3a, by which two separate wedge-shaped headpieces3bare pivotably supported. This is similar to the construction shown in more detail in the patent specification FI 83802 C.

The latch bolt3is by means of a spring5urged to its position protruding from the lock case and the lock case is provided with a stopper6for the spring5. The latch bolt3has also a deadlocking member4, which is in cooperation with the guide surface7aof a guide element7in order to accomplish deadlocking. The guide surface4aof the deadlocking member4is in cooperation with a counter surface7bof the guide element, as is described in more detail below.

The guide element7may be moved in the direction of the front plate2and the lock case is provided with relevant guiding members for guiding its movements, of which members a pin14is shown inFIGS. 1 and 7. The guide element7also comprises a protrusion7cprovided with a recess7d, and a guide groove7e, which is in cooperation with a pin15of the dead bolt13for guiding the movements of the dead bolt.

The auxiliary bolt8includes a body part8aand a guide part8b, which is in cooperation with a guiding piece10attached to the lock case. The auxiliary bolt8is by means of a spring9urged to, its protruding position and the spring9is also supported to a counter surface10bin the guiding piece10. In addition, the arrangement comprises a stop member11, which is movably supported by the body part8aof the auxiliary bolt and pressed by a spring12toward the lock case. The auxiliary bolt8may on one hand move relative to the stop member11and on the other hand the stop member is turnable relative to the body part8aof the auxiliary bolt. Guide surfaces10aof the guiding piece10define the turning freedom of the stop member11.

The operation of the arrangement is as follows. In the situation according toFIGS. 1 and 2, where the latch bolt3and the auxiliary bolt8are out, which corresponds to the open position of the door, the stop member11is in the recess7dof the guide element, whereby it prevents the guide element7from moving downwards in the figures to a position deadlocking the latch bolt3. At the same time the recess7dprevents the stop member11from turning away from this position in spite of the loading caused by the spring12.

In the situation according toFIGS. 3 and 4only the auxiliary bolt is pressed into the lock case. In this case both springs9and12yield, but the stop member11keeps the guide element7still in its upper, non-deadlocking position, whereby the door may still be pushed to its closed position without any operational means.

FIGS. 5 and 6show a situation where both the latch bolt3and the auxiliary bolt8are pressed into the lock case1, which relates to pushing the door to its closed position. Thus, at the same time as the latch bolt3moves inwards, the guide surface4aincluded therein hits the counter surface7bof the guide element and moves the guide element7somewhat upwards in the figures so that the stop member11is released from the impact of the recess7dand turns, urged by the spring12, to the position illustrated inFIGS. 5 and 6.

After this, when the door is completely closed, the latch bolt3is allowed to move into the bolt opening (not shown) in the striker plate of the lock in the doorframe, but the striker plate prevents the protrusion of the auxiliary bolt8. This corresponds to the situation inFIGS. 7 and 8. At the same time as the latch bolt3is moved out, the stop face7bof the guide element is released from the impact of the guide surface4aof the latch bolt3. Since the stop member11is still urged by the spring12to its turned position shown inFIGS. 5-8, the guide element7is allowed to move to its lower position shown inFIGS. 7 and 8, where it provides the deadlocking of the latch bolt3by means of its guide surface7a. If the aim is to open the door, it requires moving of the guide element7again to its upper position according toFIGS. 1 and 2, which can be accomplished by several ways known per se, for instance by a door handle, by a key, or electrically. As it appears from the figures also the dead bolt13is then movable by means of the guide groove7ein the guide element7to its retracted position enabling the opening of the door.

The invention is not limited to the above-described application, but several modifications are conceivable in the scope of the appended claims.