The locking system for a service door according to the invention and the method for locking a service door is particularly well suited to be used for locking service doors used in emergency exits.

The service doors have typically been locked with the aid of a rod mechanism located vertically within the service door.

For instance, the Finnish patent application 963685 presents an automatically locked bolt mechanism. The bolt mechanism comprises two rotating members interconnected by a spring, of which members one operates as the locking bolt of the bolt mechanism and the other as an indicator bolt. When the indicator bolt hits the frame and begins to rotate due to the frame, the indicator bolt turns the locking bolt in the same direction toward a locking position. The bolt mechanism comprises further a blocking body, which, when the bolt mechanism is in the locking position, prevents the locking bolt from rotating out from the locking position. The blocking body is moved away from the position, preventing the locking bolt from rotating, with the aid of a pulling rod fastened to the blocking body, so that pulling the pulling rod can move the blocking body.

The major problem in the bolt mechanism like that described above is that the ability to open the bolt mechanism depends on the actions of a person opening the door. The door will open only by pulling a handle connected to the pulling rod. If the bolt mechanism is damaged, e. g. due to a fire or forces directed at the door, it is not possible to open the bolt mechanism.

The bolt mechanism has a further problem in it being possible to manipulate it, in other words, it can be brought into a state where it can not be locked by locking the blocking body in a position where it does not prevent the locking bolt from rotating.

A further problem with the known opening and locking solutions, which are based on a spring force or on elements being pushed into the frame of the door in the locking step or into a free motion in the opening step, is that it is often difficult to open a door which is loaded, for instance by a pressure directed at the surface of the door.

Thus the object of the present invention is to provide a locking system for a service door and a method for locking a service door which are better than the previous ones.

Then an object is to provide such a locking system for a service door and a method for locking a service door with which the locking of the service door can be forcibly actuated, whereby the breaking of a spring or springs in the bolt mechanism will not hinder of prevent the opening of the service door.

An object is particularly to provide a locking system which has separate functions, whereby the top bolt and the bottom bolt of the service door are not structurally interconnected.

A further object is to provide a locking system which can not be manipulated and which it is not possible to open from the outside without opening the main door.

In order to attain the above mentioned objects a service door locking system according to the invention and the method for locking a service door are characterised in that what is defined in the characterising clauses of the independent claims presented below.

A locking system for a service door according to the invention comprises typically a main door, which is fastened, advantageously by hinges, to the frame of a passage, and a service door as well as a bolt mechanism arranged in the service door. In this context a main door means a door arranged in a passage or other opening intended to be closed by a door, which acts as a closing means for the normal passage. A service door means in this context a door, which used together with the main door enables the closing of a passage or other opening intended to be closed by a door, to be closed in two or more sections, whereby in such situations where the whole width of the passage is not needed, the passage is made by opening the main door, and when the whole width of the passage is

needed, also the service door is opened. The bolt mechanism comprises a first rotating member arranged on a first bolt axis parallel with the surface of the service door, the first member having at least one projection which projects outwards from the bolt axis and forms the locking bolt of the bolt mechanism, whereby this bolt in its locking position projects out from the body of the service door into a recess or the like formed in the frame of the service door. The rotating movement of the locking bolt into the locking position can be realised for instance with the aid of a second rotating member arranged on the above mentioned bolt axis, which member has a projection projecting outwards from the bolt axis and forming a first indicator bolt of the bolt mechanism, this indicator bolt forming an angle a with the locking bolt and projecting out from the body of the service door when the service door is open and the bolt mechanism is in the non-locking position. The first and the second rotating members are interconnected so that when the indicator bolt turns around the bolt axis it tends to turn the locking bolt in the same direction. The bolt mechanism further comprises a blocking body which, when the bolt mechanism is in the locking position, prevents the first rotating member from turning out from the locking position, and a moving mechanism for moving the blocking body in order to prevent the first rotating member from turning out from the locking position and moving the blocking body away from preventing the first rotating member from turning out from its locking position. In this context a blocking body means all such members formed by one or more parts, which are designed and made so that they are able to prevent the rotating movement of the locking bolt. Thus the blocking body can be for instance a pin made of metal, which is moved with the aid of a moving mechanism, or a rotating bolt, whose preventing part is moved with the aid of the moving mechanism by turning the above mentioned bolt.

Typically, the moving mechanism according to the invention comprises a rotating member arranged on a second bolt axis differing from the direction of the surface of the service door, the member having a first projection projecting outwards from the bolt axis, the projection forming the locking bolt of the moving mechanism, which bolt in the locking position projects out from the body of the service door into a recess or the like formed in the side part of the main door, and a second projection projecting outwards from the bolt axis, the second projection forming a first indicator bolt of the moving mechanism and forming an angle oc with the locking bolt and projecting out from the body of the service

door when the main door is open and when the moving mechanism is in a position where it does not move the blocking body. The moving mechanism and the blocking body are advantageously combined so that when the rotating member of the moving mechanism turns around the bolt axis due to the effect of the closing motion of the main door it tends to move the blocking body in a direction where the blocking body prevents the locking bolt from turning out from the locking position, and due to the effect of the opening motion of the main door the moving mechanism tends to move the blocking body away from the position where it prevents the turning of the locking bolt. Due to the structure of the moving mechanism and the blocking body according to the invention the locking and opening of the bolt mechanism is arranged to be forced, so that the motion of the main door both opens and closes the bolt mechanism by moving the blocking body via the moving mechanism.

In an advantageous locking system according to the invention the second bolt axis is substantially perpendicular to the first bolt axis. Due to the above mentioned angle the motion paths of the components in the bolt mechanisms are straight and thus operate positively. In addition a locking system like that described above is durable and economical to manufacture.

In an advantageous locking system according to the invention, in order to adjust the extension of the indicator bolt an adjusting member is arranged on the projection of the moving mechanism projecting outwards from the second bolt axis. Due to the adjusting member it is easy to install the locking system, as the different distances at different points between the service door and the main door can be compensated for by the adjusting member.

In an advantageous locking system according to the invention the rotating member of the moving mechanism is connected by a spring to a support member located between the first bolt axis and the second bolt axis, whereby the spring tends to return the rotating member into the open position when the main door is opened. Due to the returning motion caused by the spring the rotating member is surely in the correct position when the bolt mechanism is locked the next time when the main door is closed.

In an advantageous locking system according to the invention the first rotating member of the bolt mechanism is arranged to prevent the blocking body from

moving so that it could prevent the first rotating member from moving, before the first rotating member has turned into the locking position. Arranging to prevent the blocking body from moving means a design of the first rotating member so that a part of the rotating member is located on the motion path of the blocking body until the first rotating body has turned into the locking position.

Due to the above mentioned arranging the main door cannot be locked before the service door is in a position which can be locked.

In an advantageous locking system according to the invention the locking system comprises a holding member, which is separate from the first locking bolt and the indicator bolt, and which is arranged to keep the service door closed when the main door is open. A holding member means in this context such members which enable the service door to be kept closed without being locked, when the main door is open. Such holding members are for instance different spring loaded ball members, where the spring member presses the ball member against the frame and keeps the service door in its position. When the service door is opened the spring member yields and enables the ball to be pressed inwards, whereby the service door opens.

In an advantageous locking system according to the invention the holding member is arranged in connection with the bolt mechanism. Then the holding member can be located for instance in the frame structure of the bolt mechanism, whereby the installation of the holding member does not require separate installation procedures, such as tooling of extra holes or openings.

In an advantageous locking system according to the invention the bolt mechanism is arranged in at least one corner of the service door on the side of the main door. Then the bolt mechanism is easy to install in the service door by tooling an adapter for the bolt mechanism in the upper corner of the service door.

As there is a short distance both to the main door and to the frame, the bolt mechanism does not require any long guides, which require cumbersome installation, but the bolt mechanism can be realised as a solid mechanism with positive operation.

Typically the method according to the invention is applied for locking a service door with the aid of a locking system which comprises a main door fastened, advantageously by hinges, to the frame of the passage, and a service door as

well as a bolt mechanism arranged in the service door. The bolt mechanism comprises a locking bolt moving out from the body of the service door in order to lock the service door, which locking bolt in its locking position projects out from the body of the service door into a recess or the like formed in the frame of the service door. The bolt mechanism further comprises a blocking body which, when the bolt mechanism is in the locking position, prevents the locking bolt from moving out from its locking position, and a moving mechanism for moving the blocking body. Typically in the method according to the invention, when the service door is closed, the moving mechanism is operated with the aid of the main door. By closing the main door, its side will hit a moving mechanism in the service door, where a rotating member is thus turned and the blocking body is in this way moved to prevent the locking bolt from moving out from its locking position. At the same time the locking bolt of the moving mechanism settles into an adapter in the main door, such as into a recess or the like. By opening the main door the locking bolt hits the edge of said adapter, whereby, when the opening motion of the main door is continued, the moving mechanism moves back into its original position, and thus the blocking body is moved away from the position where it prevents the motion of the locking bolt out from its locking position.

The main advantage of the above-presented invention is that with the aid of a locking system according to the invention the locking of the service door can be realised as a separate operation, whereby the bolts installed in the upper and lower parts of the service door have no physical connection with each other.

A further advantage of the invention is that the locking system according to the invention is forcibly actuated. In other words, the locking or opening of the locking system does not depend on the force of gravity or on a bolt moved by a spring. Thus the locking system according to the invention can well resist external interfering factors, such as heat or forces directed against the system.

A further advantage of the invention is that the locking system according to the invention cannot be opened from the outside, without opening the main door, because the bolt mechanism is always double-locked in its locking position.

Below the invention is described with reference to the enclosed figures, in which Figure 1 shows as an example a part of a locking system according to the invention; Figure 2 shows as an example the bolt mechanism of the locking system according to the invention to be arranged in a service door, in its unlocked position; and Figure 3 shows as an example the bolt mechanism of the locking system according to the invention to be arranged in a service door, in its locked position.

Figure 1 shows a service door, where a part of its top corner is cut away, and where a bolt mechanism 3 is fastened to the right-hand top corner of the service door 1 with the aid of locking members 2, the bolt mechanism being in its open position. In the figures 2 and 3 the bolt mechanism 3 is shown as being removed from the service door and seen from one side. In figure 2 the bolt mechanism is in its open position and in figure 3 it is in the locking position. The bolt mechanism 3 comprises a locking member arranged on the first bolt axis 4 in parallel with surface of the service door, the locking member having an indicator bolt 5 and a locking bolt 6. A spring member is advantageously arranged between the locking bolt 6 and the bolt axis 4, whereby the spring member resists the turning motion of the locking bolt 6. The bolt mechanism 3 comprises further a blocking body 7 and a moving mechanism 8 for the blocking body 7. The blocking body 7 is made of metal by bending, and at its end towards the locking member it is bevelled. In connection with the spring member resisting turning of the locking bolt 6 it is advantageous to arrange a separate protecting member which protects the locking member from the blocking body 7. The blocking body 7 is connected to a moving mechanism 8 which comprises a rotating member arranged on a second bolt axis 9, which is perpendicular to the first bolt axis 4, and the rotating member has a first projection which projects outwards from the bolt axis 9, whereby this projection forms the locking bolt 10 of the moving mechanism, and a second projection which projects outwards from the bolt axis 9 in a 90 degrees angle regarding the locking bolt 10, whereby this projection forms the indicator bolt 11 of the moving mechanism. A detachable washer acting as an adjusting member 12 is arranged on the indicator bolt 11 for

controlling the length of the indicator bolt 11, and by changing or replacing the size and shape of the washer it is possible to adjust the extension of the indicator bolt 11. Also other means than washers can be used as the adjusting member 12, such as for instance different plates, bolts, pins or the like. Between the moving mechanism 8 and the axis 13 there can be a spring member which tends to return the moving mechanism into the open position.

In such exit passages which do not have a threshold or a frame around the passage it is possible to replace the locking bolt 6 by a pin-like member which projects into a recess or a corresponding adapter located in the side of the passage or in the base, such as in the floor. In the locking position a pin-like member of this type projects into said recess, and when the moving mechanism 8 is turned by the main door the blocking body 7 is moved to prevent the pin-like member from leaving said recess.

Alternatively the blocking body 7 can also comprise a third member which rotates in relation to a rotation axis, such as for instance the axis 13 and which, due to the motion created by the moving mechanism, turns to prevent the locking bolt 6 from turning out from the locking position. Further the blocking body 7 can be shaped so that when the moving mechanism 8 moves the blocking body 7, then the blocking body 7 forces the locking bolt 6 to be tightly pressed against the edge of a recess in the frame, whereby the service door 1 is tightly closed.

In the method according to the invention the moving mechanism 8 is typically operated with the aid of the main door, when the service door 1 is closed. By closing the main door its side hits the moving mechanism 8 in the service door 1, whereby the indicator bolt 11 of the moving mechanism is turned and the blocking body 7 is moved to prevent the locking bolt 6 from moving out from its locking position. At the same time the locking bolt 10 of the moving mechanism 8 enters the adapter in the main door, such as a recess or the like. By opening the main door the locking bolt 10 hits the edge of said adapter, and when the opening motion of the main door continues the moving mechanism 8 will move back to its original position and thus the blocking body 7 is moved away so that it will not prevent the locking bolt 6 from moving out from its locking position. The invention is not intended to be limited to the embodiment presented above as an example, but on the contrary the intention is that it can be widely interpreted within the scope defined by the claims presented below.