WO2009096892A1

WO2009096892A1 - Lock with spring bolt

Info

Publication number: WO2009096892A1
Application number: PCT/SE2009/050098
Authority: WO
Inventors: Jorma Hirvi
Original assignee: Assa Ab
Priority date: 2008-02-01
Filing date: 2009-01-30
Publication date: 2009-08-06
Also published as: SE0800251L; EP2247809A4; SE531998C2; EP2247809A1

Abstract

Lock, for doors, windows and the like, comprising a forend (10), a spring bolt (120) with a bolt latch (130) and a blocking device. The spring bolt and the bolt latch are together axially displaceable relative to the forend. The spring bolt is fixed to the bolt latch, rotatably about a rotation axis (131) which is substantially perpendicular to the direction of axial displacement of the spring bolt and of the bolt latch. The blocking device is switchable between a release position, in which rotation of the spring bolt about the rotation axis is allowed, and a blocking position, in which the position of the spring bolt relative to the bolt latch is fixed. In order to achieve a reduction of the necessary operating force, the blocking device comprises a first (160) and a second (170) linearly displaceable element, as well as at least two pairs of sliding surfaces (125, 164, 163, 174) interacting in pairs, which sliding surfaces are disposed on the spring bolt, the first displaceable element and the second displaceable element, and are arranged to convert a rotational motion of the spring bolt to the respective linear displacement motions of the first and the second displaceable element.

Description

Lock with spring bolt

Field of the invention

The invention relates to a lock for windows, doors and the like, comprising a lock housing, a spring bolt with bolt latch and a blocking device which selectively allows or prevents a rotational motion of the spring bolt relative to the bolt latch. The lock is especially well suited for use with emergency doors .

Background to the invention

Emergency or evacuation doors are often equipped with so- called emergency or panic evacuation fittings or accessories. Such fittings are disposed on the inner side of the door to allow quick and easy operation of the lock from the inner side of the door, from which evacuation through the door shall be allowed. The emergency doors are opened outwards and the fittings are configured and coupled to the bolts of the lock to allow the door to be opened with a simple thrust on a handle or a panic opening bar.

In panic situations, for example, where crowding occurs by the emergency door, it can happen that the crowd is pressed against the door before this has been opened. The spring bolt of the lock is thus pressed against the striking plate so that a friction force arises between them. A greater force is hence needed to be applied to the fitting in order to withdraw the spring bolt from its engagement with the striking plate. In order to prevent the need for excessively large forces to operate the fitting, there are safety regulations which specify how large a maximum force on the operating members of the fitting may be required to open the door when a certain pressure force is applied to the inner side of the door leaf. According to European safety regulations, for example, the necessary force upon a panic fitting to operate the lock must not exceed 220 N if a pressure force of 1000 N is applied centrally to the inner side of the door leaf .

Prior art In order to reduce the forces which need to be applied to the fitting in panic situations, it is previously known to configure the spring bolt such that it is rotatable relative to the bolt latch, about a rotation axis which is perpendicular to the direction of axial displacement of the spring bolt and of the bolt latch. In order to prevent the door from possibly opening from the outside, the rotational motion of the spring bolt can selectively be blocked and allowed by means of a blocking device operated with the emergency or panic evacuation fitting. When the door is pressed outwards and the fitting is activated, the blocking device of the spring bolt is released, so that the spring bolt can be rotated in the direction away from the striking plate, whereupon the friction between them decreases. The force which is required to release the spring bolt from engagement with the striking plate is thereby reduced.

DE 102 07 630 Al describes a lock having a latch bolt which is axially displaceable together with a latch carrier and is rotatable relative to the latch carrier. The lock also comprises an electrically operable blocking device, with which the rotational motion of the latch relative to the latch carrier can be blocked or allowed. The construction shown in DE 102 07 630 Al comprises a number of lever arms, which makes it relatively complicated and bulky. The device which is described therein additionally entails that the whole or a relatively large part of the force with which the striking plate is pressed against the spring bolt is transmitted to that part of the blocking device at which the release of the rotational motion of the latch shall be achieved. There is hence a risk that a relatively large force, transmitted from the striking plate, will cause a high friction between the parts of the blocking device, whereby the force required to release the blocking device is high.

EP 1 291 478 Al describes another lock having a spring bolt which is axially displaceable together with a bolt latch and is rotatable in relation to the latter. A blocking device for selectively releasing and blocking the rotational motion of the spring bolt comprises a contact roller which is disposed on a rocker arm and which, in contact with two different surfaces on a linearly displaceable part of the blocking device, can selectively allow and prevent linear displacement of this part so as thereby to allow or prevent rotation of the spring bolt. This device, too, is relatively bulky and complicated. Though the use of a rotating roller helps to reduce the friction in the blocking device, it simultaneously increases the spatial requirement, as well as the complexity of the device and the material and production costs.

Summary of the invention

One object of the present invention is therefore to provide a lock having an improved device for selectively allowing and preventing rotation of a spring bolt relative to a bolt latch which is axially movable together with the spring bolt.

Another object is to provide a lock of the kind which requires small operating forces in order to release the spring bolt for rotation, even when a large force on the door leaf presses the spring bolt into contact against the striking plate.

A further object is to provide a lock of this kind which is space-saving.

Another object is to provide a lock of this kind in which the spring bolt, the bolt latch and the blocking device can be configured as a modular unit for simple mounting in a modularized lock production system.

Yet another object is to provide a lock of this kind which can be realized relatively cheaply and with simple construction parts .

These and other objects are obtained with a lock of the type which is defined in the preamble to Patent Claim 1 and which has the special technical features defined in the characterizing part of the claim. The lock is intended for doors, windows and the like, and especially for outward- opening emergency doors which on their inner side are provided with emergency or panic evacuation fittings for operation of the lock. The lock comprises a forend, a spring bolt with a bolt latch and a blocking device. The spring bolt and the bolt latch are together axially displaceable relative to the forend. The spring bolt is fixed to the bolt latch, rotatably about a rotation axis which is substantially perpendicular to the direction of axial displacement of the spring bolt and of the bolt latch. The blocking device is switchable between a release position, in which rotation of the spring bolt about the rotation axis is allowed, and a blocking position, in which the position of the spring bolt relative to the bolt latch is fixed. According to the invention, the blocking device comprises a first and a second linearly displaceable element, as well as at least two pairs of sliding surfaces interacting in pairs, which sliding surfaces are disposed on the spring bolt, the first displaceable element and the second displaceable element and are arranged to convert a rotational motion of the spring bolt into respective linear displacement motions of the first and the second displaceable element.

The invention is based on the insight that it is possible to prevent self -locking of the blocking device for the rotation of the spring bolt by reducing the force which is transmitted from the spring bolt to the parts of the blocking device when the door is pressed outwards and the striking plate exerts a force upon the spring bolt. With the two linearly movable elements and the two pairs of interacting sliding surfaces for transmitting the force from the striking plate via the spring bolt and the two displaceable elements, it is possible to achieve a two-step gear mechanism, by which the transmitted force is reduced in two steps. By configuring the interacting sliding surfaces at a suitable angle in relation to the motional direction of the respective moving part, it is possible to adjust the gearing, i.e. the force reduction for each gear step. In the blocked position, the force is transmitted from the striking plate via the spring bolt and the two displaceable elements to a switchable blocking member, which in turn transmits the force to the lock housing. Owing to the force reduction which is achieved by means of the two pairs of interacting sliding surfaces, the force with which the second displaceable element is in contact with the blocking member will be small. These two elements are thereby deterred from mutual self-locking, which would otherwise result in a greater force requirement for switching the blocking member from its blocking position to its release position. With the invention, the force which is required to release the blocking device when the door is pressed outwards in an opening instance is therefore reduced. This in turn helps to reduce the force which has to be applied to a fitting coupled to the lock in order in an emergency situation, for example, to open the door when it is pressed outwards with great force. In other words, the force-reducing pairs of interacting sliding surfaces according to the invention afford a better control over the forces transmitted from the striking plate into the lock when the door is pressed outwards with the spring bolt engaged with, the striking plate.

The sliding surfaces, interacting in pairs, can be variously configured as long as their configuration produces a reduction of the force in the motional direction which is transmitted between them. For example, the sliding surfaces can be constituted by plane, single-curved or double-curved surfaces. One pair of interacting sliding surfaces, which during rotation of the spring bolt transmits the force from the spring bolt to the first linearly displaceable element, is suitably configured with a concave or a convex single-curved surface. The other pair of interacting sliding surfaces suitably comprises a conical surface, which is disposed on the first linearly displaceable element, and a plane surface, which is disposed on the second linearly displaceable element. The motional directions of the first and second linearly displaceable elements are suitably arranged perpendicular to each other, and the conical surface as well as the plane surface are suitably configured at an angle of around 60° and 30° respectively to the motional direction of the respective element.

With the force and motion transmission which is thus achieved, the constituent components can be made very small. The first and second displaceable elements are here suitably accommodated in the bolt latch. A very compact and space- saving device is thereby obtained.

The blocking device suitably comprises an operating follower, which can be actuated by an emergency evacuation fitting, a panic evacuation fitting, or the like, for switching between a blocking position, in which motion of the second displaceable element is prevented, and a release position, in which linear motion of the second displaceable element is allowed. In this case, the blocking device suitably comprises a pivotable flap, which is disposed between the second displaceable element and a blocking arm fixed to the operating follower.

The lock suitably comprises a base plate, in which the bolt latch is accommodated in a guided manner for axial displacement and to which the operating follower is rotatably fixed. The base plate, the spring bolt with the bolt latch and the blocking device in this way suitably form a modular unit, which can be easily mounted on a forend unit integral to the lock.

The modular unit suitably also comprises an deadlocking latch and an deadlocking blocking device, which are movably arranged at the base plate .

Further objects and advantages of the lock according to the invention emerge from the following detailed description and from the following patent claims.

Brief description of the figures

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

Fig. 1 is an exploded diagram of a lock according to one embodiment according to the invention.

Figs. 2a-c are a perspective view from the rear, a side view and a perspective view from the front of a forend unit integral to the lock shown in Figure 1.

Fig. 3 is a perspective view of a modular unit integral to the lock shown in Figure 1.

Fig. 4. is an exploded diagram of the modular unit shown in Fig. 3. Figs. 5a and 5b are schematic plan views, partially in cross section, of certain parts of the modular unit shown in Fig. 3.

Figs. 6a-e are outline diagrams of certain parts integral to the modular unit shown in Fig. 3, when they assume different positions.

Detailed description of embodiments

That embodiment of the lock according to the invention which is shown in the figures comprises a number of modules forming part of a modular system. The modular system also comprises other modules, which can be combined with the modules shown in the figures in order to achieve other functions of the lock.

With reference to Fig. 1, the lock comprises a forend unit 10, which constitutes the mounting base for the lock. The forend unit 10 comprises a lock forend 11 and a mounting bar 12 of U- shaped cross-sectional profile, which is fixed to the forend 11 and which has two mounting plates 13, 14 projecting in parallel rearwards from the forend (see also Fig. 2a) . On the forend unit there are disposed a cylinder follower module 20, an evacuation follower module 30 and a handle follower module 40. These can be operated in a conventional manner by means of a lock cylinder, an emergency fitting, such as an emergency evacuation fitting or a panic evacuation fitting, or a handle (not shown) via traditional members (not shown) accommodated in central openings in the respective follower.

To the forend unit there is additionally fixed a hook bolt module 50, as well as two plates 61, 62, which together form a lock case and which constitute the top and bottom of the case. The various modules of the lock (10, 20, 30, 40, 50, 61, 62) are held together in a conventional manner by screws and sleeve nuts.

As can most clearly be seen from Fig. 2b, a spring bolt module 100 is additionally disposed on the forend unit 10 and is fixed to this by means of a pin 101, which extends through corresponding openings in the mounting plates 13, 14.

The spring bolt module 100 is shown in greater detail in Figures 3 and 4 and its constituent components will now be described. The spring bolt module 100 comprises a base plate 110, a spring bolt 120, a bolt latch 130, an operating follower 140 and an deadlocking latch 150. The spring bolt 120 is rotatably fixed to the bolt latch 130 by means of a shaft journal 131, which is accommodated in corresponding through openings in the spring bolt and the bolt latch. The bolt latch 130 is accommodated in a guided manner between opposing guide surfaces 111, 112 of the base plate 110. The bolt latch 130 and the spring bolt 120 fixed thereto can therefore be displaced rectilinearly in relation to the base plate 110 and thus in relation to the lock housing formed by the forend unit 10 and the plates 61, 62. In Figure 1, the spring bolt 120 and the bolt latch 130 are shown in an extended position.

The deadlocking latch 150 is accommodated in an axially displaceable and guided manner by the base plate 110, between guide surfaces 113, 114. The motion of the deadlocking latch 150 is regulated by a pivotable blocking device 151, which is rotatably fixed to the base plate 110, and a spring 152, which, via a ball 153, communicate with a shaft 160 accommodated in the bolt latch 130. The working of the interlocking latch is not described here in detail.

The spring bolt 120 has a front portion 121 disposed on one side of the shaft journal 131 and having two oblique latch surfaces 122, 123 arranged symmetrically in relation to a central plane, in parallel with the shaft journal 131. On the opposite side of the shaft journal, the spring bolt 120 has a rear asymmetrical portion 124. This portion 124 has a sliding surface 125. This sliding surface has a single-curved portion 125a and a plane portion 125b.

In the bolt latch 130 there is accommodated a first element, in the form of a peg or shaft journal 160, which is axially displaceable in parallel with the motional direction of the bolt latch. More precisely, the shaft journal 160 is accommodated in an axially displaceable manner in a circular- cylindrical first barrel 133, which is disposed in a portion of the bolt latch 130 which is disposed distally to the spring bolt 120. The shaft journal 160 has a front portion 161 of greater cross-sectional diameter and a rear portion 162 of lesser cross-sectional diameter. The two portions are joined by an intermediate conical portion with a cone angle of around 60°. This conical portion forms a rear sliding surface 163 on the shaft journal 160. The barrel 133 has correspondingly a front portion 134 of greater diameter and a rear portion 135 of lesser diameter for the tight-fitting reception of the front 161 and rear 162 portions of the shaft journal 160.

At that end of the front portion 161 of the shaft journal 160 which faces the spring bolt 120, there is disposed a single- curved front sliding surface 164. The radius of curvature of this sliding surface 164 substantially corresponds to the radius of curvature of the single-curved portion 125a of the sliding surface 125 of the spring bolt 120. A compression spring 166 is accommodated in the rear portion 135 of the first barrel 133 and in a rearward-opening circular- cylindrical recess 167 in the rear portion of the shaft journal 160. The compression spring 166 thus presses the shaft journal 160 in the direction of the spring bolt 120.

The bolt latch 130 also has a second barrel 136, which extends perpendicularly from the front portion 134 of the first barrel 133 and which opens out on a side face of the bolt latch 130. The second barrel 136 has a rectangular cross section and receives, in straight -line guidance, a second linearly displaceable element in the form of a blocking plate 170. A stop pin 137 is fixed to the bolt latch 130 such that it projects into the second barrel to prevent the blocking plate 170 from being led out of the barrel 136 through the opening on the side face of the bolt latch. The blocking plate 170 has two mutually opposing side faces 171, 172, which are parallel with the motional direction of the blocking plate and which, in contact with the corresponding walls of the second barrel

136, guide the motion of the blocking plate. On the end facing the first barrel 133 there is disposed a plane end face 173. The blocking plate further has a sliding surface 174, which is arranged as a plane side face connecting the faces 171 and 173. The plane sliding surface 174 has an angle of around 30° to the axial motional direction of the blocking plate, and thus to the side faces 171, 172. The blocking plate 170 additionally has a stop face 175 opposite to and parallel with the end face 173. The stop face 175 is connected to the side face 171 by an oblique connecting surface 176.

The base plate 110 comprises a wing-shaped portion 115, on which a first seat 116 for the rotatable operating follower

140 is disposed. A second seat 117, which receives a pivotable blocking flap 180, is also disposed on the wing-shaped portion 115. The operating follower 140 is rotatably fixed to the first seat 116 and has a radially projecting operating arm 141 and a radially projecting blocking arm 142, with which the rotational position of the blocking flap 180 can be influenced. The operating follower 140 can be driven into rotation, according to the figures in the clockwise direction, by means of a driver 41 (see Fig. 1), which bears against the operating arm 141 and which is coupled to the handle follower module 40. The handle follower module 40 is additionally coupled together with the emergency follower module 30 and the cylinder follower module 20. Each rotation in the direction of opening of the respective follower in these modules therefore causes the operating follower 140 to be rotated clockwise towards a release position.

The blocking device for selectively preventing and allowing rotation of the spring bolt 120 about the axis 131 comprises the rear portion 124 of the spring bolt, the shaft journal 160, the compression spring 166, the blocking plate 170, the blocking flap 180 and the operating follower 170. The shaft journal 160 constitutes a first linearly displaceable element and the blocking plate constitutes a second linearly displaceable element. The shaft journal 160 and the blocking plate 170 are displaceable in the respective motional directions, which are defined by the first 133 and the second 136 barrel, which barrels are perpendicular to each other. The blocking device further comprises two pairs of interacting sliding surfaces. The first pair of sliding surfaces is constituted by the sliding surface 125 on the rear portion of the spring bolt 120 and the front sliding surface 164 on the front portion 161 of the shaft journal. The second pair of sliding surfaces is constituted by the conical rear sliding surface 163 of the shaft journal and the plane sliding surface 174 on the blocking plate 170.

With reference to Figs. 5a-b and 6a-e, the working of the lock will now be described. In the position shown in Fig. 6a, the spring bolt 120 and the bolt latch 130 are in their extended position. This position is corresponded to by that position for the spring bolt 120 which is shown in Figs. 1, 3 and 5a. The spring bolt 120 is accommodated in a striking plate (not shown) , which can be disposed, for example, in a door frame or in the inactive door if the lock is used in a double door. The holding side 123 of the spring bolt 120 bears against the striking plate. As can be seen from Fig. 5a, the holding side 123 is substantially parallel with the door leaf. The single- curved portion 125a of the sliding surface 125, belonging to the spring bolt 120, bears against the front sliding surface 164 of the shaft journal 160. The rear sliding surface 163 of the shaft journal 160 bears against the sliding surface 173 of the blocking plate 170. The stop face 175 of the blocking plate (see Fig. 4) bears against the blocking flap 180. The blocking flap 180 bears with a stop face 181 against an end face 143 on the blocking arm 142 of the operating follower 140. The operating follower 140 is in its blocking position, the contact of the blocking arm 142 against the blocking flap 180 preventing rotation of the blocking flap. Displacement of the blocking plate 170 and of the shaft journal 160 is also thereby prevented, the spring bolt 120 being prevented from rotating about the axis 131. The blocking device is therefore in its blocking position.

When the door has to be opened quickly, for example in an emergency or panic situation, to allow evacuation through the door, a person presses on the emergency or panic evacuation fitting which is coupled to the emergency follower in the emergency follower module 30. The emergency follower is then made to rotate and this rotational motion is transmitted in a conventional manner to the driver 41. The driver 41 in turn actuates the operating follower 140, such that this rotates clockwise according to the figures. The operating follower 140 then assumes the position shown in Fig. 6b. As can be seen from the figure, the end face 143 on the blocking arm 142 of the operating follower 140 has been removed from its blocking contact against the stop face 181 of the blocking flap 180, so that the blocking flap has rotated clockwise into the position shown in Fig. 6b. The blocking plate 170 is hence free to be displaced outwards in the direction of the operating follower in the barrel 136. In the example shown in Fig. 6b, the blocking plate, under the influence of gravity, has undergone this displacement. This can happen, for example, if the operating follower 140 is set in rotation without any force being applied to the holding side 123 of the spring bolt 120. Such a force upon the holding side 123 is normally present, however, in which case the shaft journal 160 is displaced to the right and the spring bolt 120 is rotated as soon as the blocking plate 170 is free to be displaced outwards. Once the blocking plate 170 has been released, the shaft journal 160 is thus free to be displaced to the right in the first barrel 133 and the spring bolt 120 is free to be rotated about the axis 131 in the direction indicated by the arrow in Fig. 5b.

In that position for the blocking device which is shown in Fig. 6b, the application of a force outwards onto the door leaf will cause the striking plate to act with a force upon the holding side 123 of the spring bolt 120. The spring bolt is then allowed to rotate about the axis 131 and, by virtue of the contact between the sliding surfaces 125 and 164, to press the shaft journal inwards, to the right, in the barrel 133. The shaft journal 160 escapes from the extended blocking plate 170 and only the relatively small force from the compression spring 166 must be surmounted to allow rotation of the spring bolt 120. Fig. 6c shows the position for the parts of the blocking device once the spring bolt 120 has performed a part of its rotation.

In this position, the holding side 123 of the spring bolt 120 has been tilted in relation to the striking plate. If the force upon the door leaf persists, the force which the striking plate exerts upon the spring bolt will firstly cause the spring bolt 120 together with the bolt latch 130 to be linearly displaced relative to the base plate 110 in the inward direction (to the right in the figures) , and will secondly cause the spring bolt 120 to complete its rotation about the axis 131. During this rotation, the plane portion 125b of the sliding surface 125 of the spring bolt comes to bear against the front sliding surface 164 of the shaft journal 160. The shaft journal is hereupon displaced further inwards in the barrel 133, the parts of the blocking device assuming the positions shown in Fig. 6d.

If the force upon the door leaf persists, the striking plate, finally, will press the spring bolt 120 and the bolt latch 130 into the fully extended position shown in Fig. 6d. The spring bolt 120 thus escapes from the striking plate and the door can be opened.

As can be seen from the above description, it is therefore possible to open the door very easily by simply pressing on the evacuation fitting and, at the same time, pushing the door outwards .

If an outwardly directed force is applied to the door leaf when the blocking device is in the blocking position shown in Fig. 6a for the rotation of the spring bolt, the striking plate will exert a force upon the spring bolt, which force is parallel with the normal direction of the holding side 123. This force strives to rotate the spring bolt 120 about the axis 131 in the arrow direction shown in Fig. 5b. The force is transmitted, by lever action about the axis 131, to the contact surface between the sliding surface 125a of the spring bolt and the front sliding surface 164 of the shaft journal. The direction of rotation of the spring bolt 120 is non- parallel with the only possible motional direction into which the shaft journal 160 is guided by the base plate 110. In order to achieve a displacement of the shaft journal 160, the respective contact surfaces on the spring bolt 120 and the shaft journal 160 are configured for this purpose as sliding surfaces 125, 164, which allow these contact surfaces to slide in relation to each other. In order to achieve a displacement of the shaft journal 160, the contact surface between them, throughout the displacement of the shaft journal 160, must also have an angle to the axial motional direction of the shaft journal, which angle cannot be perpendicular to or parallel with the axial motional direction of the shaft journal. Owing to this angle between the contact surface and the motional direction of the shaft journal 160, the force component transmitted from the spring bolt to the shaft journal, which is parallel with the motional direction of the shaft journal, is less than the total force which the spring bolt exerts upon the shaft journal. Other force components transmitted to the shaft journal are absorbed by the bolt latch 130 and transmitted to the base plate 110. Thus the force which, via the shaft journal, is relayed from the spring bolt 120 to the blocking plate 170, and subsequently onwards to the contact surface between the blocking arm 142 of the operating follower 140 and the blocking flap 180, is thereby successfully reduced.

Correspondingly, the contact surface between the rear sliding surface 163 of the shaft journal 160 and the sliding surface 174 of the blocking plate 170 has an angle which is not perpendicular to or parallel with the motional direction for the blocking plate, which motional direction is guided by the second barrel 136. Hence, the force component which is relayed by the blocking plate 170 to the blocking flap 180 will also be less than the force with which the shaft journal 160 acts upon the blocking plate 170. Other force components transmitted to the blocking plate 170 are absorbed by the bolt latch 130 and are transmitted to the base plate 110. At the contact surface between the shaft journal 160 and the blocking plate 170, a further reduction of the force transmitted from the striking plate to the contact surface between the blocking flap 180 and the blocking arm 142 of the operating follower 140 is therefore achieved.

With the lock according to the invention, a two-step force reduction of the force transmitted from the striking plate to the contact surface between the blocking flap 180 and the blocking arm 142 of the operating follower, when the door is pressed outwards in the closed state, is therefore achieved. This force reduction is of considerable importance, since it leads to a reduced friction between the blocking arm 142 and the blocking flap 180 when the operating follower 140 shall be rotated into its release position to allow rotation of the spring bolt 120 about the axis 131. The reduced friction in turn results in only a small force needing to be applied to the operating follower 140 in order to rotate this into its release position, even when very large forces are pressing the door outwards in the closed state. This also reduces the force upon the emergency fitting which is necessary to release the spring bolt and thus permit opening of the door and evacuation through the same. Even if, for example, a crowd is pressed against the door in an emergency or panic situation, it is thus sufficient to apply a small force to the emergency or panic evacuation fitting in order to open the door and allow evacuation. The invention further helps to ensure that the European safety requirements placed upon emergency doors, as regards maximum necessary operating force upon the fitting in relation to force applied to the door leaf, can be met.

Above there is described one illustrative embodiment of the invention. It will be appreciated that the description is not limiting for the invention, but that this can be freely varied within the scope of the following patent claims. For example, the pairs of interacting sliding surfaces can be configured with other geometries than those described above. For example, the sliding surfaces can be plane, symmetrically single- curved, symmetrically double-curved, or otherwise curved. A specific example is that at least one pair of interacting sliding surfaces comprises a convex spherical sliding surface disposed on a ball, and a concave spherical sliding surface disposed on a movable element. In order to achieve the desired reduction in the force transmitted from one to the other of the elements provided with sliding surfaces, the contact surface between the two sliding surfaces must be configured at a certain angle in relation to the motional direction of at least one element. In each pair of sliding surfaces, it may be expedient, if the elements are configured in softer material, for the two interacting sliding surfaces to correspond geometrically to each other. This produces a larger contact surface between them, in which case the contact pressure reduces to a corresponding degree.

Above there is also described an embodiment having two axially displaceable elements provided with sliding surfaces. It will be appreciated that the lock can comprise more than two such displaceable elements and that such an alternative embodiment can yield a further reduction of the force transmitted from the lock plate to the contact surface of the blocking device, in which release of the blocking device is achieved by the mutual separation of two contact surfaces.

It will also be appreciated that the lock, instead of being provided with a spring bolt and a hook bolt, can comprise, for example, just one spring bolt, two spring bolts or any other combination of bolts including at least one spring bolt. In addition, the number and type of followers or other members for operating the lock can, of course, be freely chosen.

Claims

1. Lock, for doors, windows and the like, comprising a forend (10) , a spring bolt (120) with a bolt latch (130) and a blocking device, in which lock; - the spring bolt and the bolt latch are together axially displaceable relative to the forend,

- the spring bolt is fixed to the bolt latch, rotatably about a rotation axis (131) which is substantially perpendicular to the direction of axial displacement of the spring bolt and of the bolt latch, and

- the blocking device is switchable between a release position, in which rotation of the spring bolt about the rotation axis is allowed, and a blocking position, in which the position of the spring bolt relative to the bolt latch is fixed, characterized in that the blocking device comprises a first (160) and a second (170) linearly displaceable element, as well as at least two pairs of sliding surfaces (125, 164, 163, 174) interacting in pairs, which sliding surfaces are disposed on the spring bolt, the first displacement element and the second displaceable element and are arranged to convert a rotational motion of the spring bolt into respective linear displacement motions of the first and the second displacement element.

2. Lock according to Claim 1, in which the first pair of interacting sliding surfaces comprises a curved first surface (125) disposed on the spring bolt (120) and a curved second surface (164) disposed on the first displaceable element (160) .

3. Lock according to any one of Claims 1 or 2 , in which the second pair of sliding surfaces comprises a conical first surface (163) disposed on the first displaceable element (160) and a plane second surface (174) disposed on the second displaceable element (170) .

4. Lock according to any one of Claims 1-3, in which the first (160) and second (170) displaceable elements are accommodated in the bolt latch (130) .

5. Lock according to any one of Claims 1-4, in which the blocking device comprises an operating follower (140), which can be actuated by an emergency accessory or the like, for switching between a blocking position, in which motion of the second displaceable element (170) is prevented, and a release position, in which linear motion of the second displaceable element is allowed.

6. Lock according to Claim 5, in which the blocking device comprises a pivotable blocking flap (180) , which is disposed between the second displaceable element (170) and a blocking arm (142) fixed to the operating follower (140) .

7. Lock according to any one of Claims 5-6, comprising a base plate (110) in which the bolt latch (130) is accommodated in a guided manner for axial displacement, and at which the operating follower (140) is rotatably fixed, the base plate (110) , the spring bolt (120) with the bolt latch (130) and the blocking device constituting a modular unit (100) mountable on a forend unit (10) comprised in the lock.

8. Lock according to Claim 7, in which the modular unit comprises an deadlocking latch bolt (150) and an deadlocking blocking device (151) , which are movably arranged at the base plate (110) .